Re: [Sam-users] Floppy drive belt

[Thomas Harte]

If you found any US suppliers and nobody has responded to you privately
then I'm happy to help out; otherwise I'm afraid I can't be of much use.

On Sat, 27 Nov 2021 at 12:19, Aleš Keprt  wrote:

> Dear Sam Coupé friends,
>
> my Sam floppy drive does not work and I thought it was not possible to
> repair it. I have also a few PC floppy drives, but I don't have the adapter
> board, so I would like to repair the original Citizen drive. I received
> information that it is actually quite easy to repair, because it should be
> possible to buy a new drive belt. And it is the same as in ZX Spectrum +3
> drive, so there are several sources where it can be bought. (Even Farnell
> has it. :-))
>
> It seemed good before I realized all eshops where I found it are in the UK
> = outside of the European Union. So my question is simple: Is there anybody
> who can send it to me from the European Union or who can send it from UK as
> a private person, not UK eshop, so I don't need to pay those high customs
> fees (which are mandatory after brexit and make the final price of these
> cheap items like 4-times higher)?
>
> And one more question: Please let me know if you also did this repair.
> Just to verify that it really works. (I think it could work - the drive
> seems alive and pretty fine, except the rubber belt.)
>
> Cheers,
> Aleš Keprt
> ___
> sam-users mailing list
> sam-users@nvg.ntnu.no
> http://nvg.ntnu.no/mailman/listinfo/sam-users
>
___
sam-users mailing list
sam-users@nvg.ntnu.no
http://nvg.ntnu.no/mailman/listinfo/sam-users

Re: Pang is amazing

[Thomas Harte]

I guess you've all become Facebook people or something?

I'll remember to check World of Sam more frequently.

On Tue, 13 Nov 2018 at 08:27, Adrian Brown 
wrote:

> Probably 
>
>
>
> APB Computer Services Ltd
>
> Registered Address: 1 Higher Larrick, Trebullet, Launceston, Cornwall.
> PL15 9QH.
>
> Telephone: +44-1566-782908
>
> email: enquir...@apbcomputerservices.co.uk
>
> Company registered in England and Wales, Number: 4942193
>
> VAT Registration Number: 826 0005 70
>
> This email and any files transmitted with it are confidential and intended
> solely for the use of the individual or entity to whom they are addressed

Pang is amazing

[Thomas Harte]

Having been mentioned as complete only once on this list in passing, and
hidden inside of Stars and Sprites, I've only just discovered Pang thanks
to a chance visit to World of Sam.

It's amazing! Only the resolution difference signals that it's not the
arcade hardware somehow hidden inside the Sam.

I can only assume I'm the last to know?

Re: Who are Andrews UK?

[Thomas Harte]

I’d crowdfund it. Though if they’ve also grabbed the Jupiter Ace, one imagines 
that any plans, however hypothetical, would be for some sort of omnibus 
machine. I don’t see the one with no games and a stack-based programming 
language selling like hot cakes.

> On 13 Apr 2018, at 16:55, Graeme Gregory <x...@xora.org.uk> wrote:
> 
> Sam Coupe Mini?
> 
> On Fri, 13 Apr 2018, at 9:17 PM, RWAP Software wrote:
>> Paul Andrews (Andrews UK) is part of the team behind the original 
>> Sinclair Vega and Vega+ (not the version which Retro Computers Limited 
>> are still struggling to get out to Kickstarter backers), and theC64Mini 
>> which has come out recently.
>> 
>> Rich Mellor RWAP Software www.rwapsoftware.co.uk www.sellmyretro.com
>> 
>> On 2018-04-13 21:01, Thomas Harte wrote:
>>> Per both Wikipedia and, more convincingly, the UK Intellectual
>>> Property Office, they registered the 'Sam Coupe' trade mark in May
>>> last year for software and hardware.
>>> 
>>> They also seem to have gone after Jupiter Ace, ZX80, ZX81 and Sinclair
>>> Spectrum so it might just be a name grab but they seem primarily to be
>>> a Luton-based vanity publisher per https://andrewsuk.com/ (which gives
>>> the same address as that with the IPO, so it's the same company) and
>>> there's no obvious value in a trade mark you're not actually going to
>>> use and that nobody else is using so my theories end there.
>>> 
>>> Does anybody have any more concrete ideas?

Who are Andrews UK?

[Thomas Harte]

Per both Wikipedia and, more convincingly, the UK Intellectual Property
Office, they registered the 'Sam Coupe' trade mark in May last year for
software and hardware.

They also seem to have gone after Jupiter Ace, ZX80, ZX81 and Sinclair
Spectrum so it might just be a name grab but they seem primarily to be a
Luton-based vanity publisher per https://andrewsuk.com/ (which gives the
same address as that with the IPO, so it's the same company) and there's no
obvious value in a trade mark you're not actually going to use and that
nobody else is using so my theories end there.

Does anybody have any more concrete ideas?

Re: Advice requested

[Thomas Harte]

If it's not too far off-topic, is the linked upscaler smart enough not to
deinterlace a progressive signal? Even though progressive signals are
off-spec for that era of video?

I'm also an ex-pat and have found that my TV is perfectly happy with a 50Hz
composite signal but its deinterlacing
is non-negotiable. So everything that moves looks pretty bad. I have not
tried any external solutions.

On 26 December 2017 at 10:58, Jason Thacker  wrote:

> Thanks!
>
>
>
> *From:* owner-sam-us...@nvg.ntnu.no [mailto:owner-sam-us...@nvg.ntnu.no] *On
> Behalf Of *Simone Voltolini
> *Sent:* Tuesday, December 26, 2017 10:43 AM
> *To:* sam-users@nvg.ntnu.no
> *Subject:* R: Advice requested
>
>
>
> That HDMI upscaler is PERFECT for Sam/Speccy/ZX81/QL 
>
>
>
> I use it for all 4 machines 
>
>
>
>
>
>
>
>
>
>
>
> Kora Sistemi Informatici
>
> Via Cavour 1, 46030 San Giorgio di Mantova MN
> Tel/Fax +39 0376 371059 <+39%200376%20371059>
> P. IVA: 02048930206
>
>
>
>
>
>
>
>
>
>
>
> *Da:* owner-sam-us...@nvg.ntnu.no [mailto:owner-sam-us...@nvg.ntnu.no
> ] *Per conto di *Jason Thacker
> *Inviato:* martedì 26 dicembre 2017 16:34
> *A:* sam-users@nvg.ntnu.no
> *Oggetto:* Advice requested
>
>
>
> Thanks to some generous relatives, I have had my Sam shipped over from the
> UK to the USA (where I now live).
>
>
>
> Voltage is not a concern, step up converters are cheap on Amazon. But I
> would like to be able to display the image from the Sam on my TV and
> unfortunately SCART sockets were never put on American TVs.
>
>
>
> What would be the best option for converting the SCART to an HDMI
> connector? Would something like this be OK?
>
>
>
> https://www.amazon.com/CiBest-Converter-Adapter-Support-Set-
> top/dp/B06Y43RVLH/ref=sr_1_3?ie=UTF8=1514302351=8-3&
> keywords=scart+to+hdmi+converter
>
>
>
> Any help/advice gratefully accepted.
>
>
>
> Thanks,
>
>
>
> Jason
>

Re: who

[Thomas Harte]

I have recently been puzzling again on the topic of efficient division as I
think I've finally resolved the precision problems that blocked my
first-person efforts last time. But I've yet to so much as install an
assembler, so that doesn't mean a lot.

On 26 November 2017 at 17:38, Andrew Park  wrote:

> Still here too, I'm working on Hunchback at the moment
>
> -Original Message-
> From: owner-sam-us...@nvg.ntnu.no [mailto:owner-sam-us...@nvg.ntnu.no] On
> Behalf Of Simone Voltolini
> Sent: 26 November 2017 16:44
> To: sam-users@nvg.ntnu.no
> Subject: R: who
>
> Please finish it: Sam scene need new stuff and all to be ported, for me,
> in Physical format.
>
> Sam need to reborn again.
>
> Great job!!!
>
>
>
> --Simon
>
>
>
>
> -Messaggio originale-
> Da: owner-sam-us...@nvg.ntnu.no [mailto:owner-sam-us...@nvg.ntnu.no] Per
> conto di Balor Price
> Inviato: domenica 26 novembre 2017 17:25
> A: sam-users@nvg.ntnu.no
> Oggetto: Re: who
>
> Hey everyone!
>
> I'm still here too.   When time permits I'm working on SAM versions of
> Thrust, Celeste, Split Personalities, and an assortment of other
> never-to-be-completed projects...
>
> Cheers
> -Howard
>
>
>

Re: OT: Email list about Forth on Sinclair (and Z80) computers

[Thomas Harte]

I wouldn't mind seeing those ROMs and circuit diagrams; I'm unlikely to be
much help with the documentation. Assuming it's all free for
redistribution, of course?

On 2 November 2015 at 21:53, Stuart Brady  wrote:

> On Tue, Nov 03, 2015 at 12:48:09AM +0100, Marcos Cruz wrote:
> > Sorry if this is a bit off-topic.
> >
> > An email list has just been created to discuss the Forth programming
> > language on Sinclair (and Z80) computers:
> >
> > http://programandala.net/en.forth-sinclair.html
>
> Cool!
>
> OT too, but I've been wanting to emulate the Hobbit (ZX Spectrum clone)
> in Fuse for a while, as this has a Forth mode.  Black Cat has sent me
> schematics for the machine but it's all somewhat outside my comfort zone.
> I also have the ROM images for the machine, and extension documentation,
> in Russian, which we can translate.
>
> If you, or anyone else would like to help me to make sense of the
> hardware I think this would be a great project. :-)
>
> I'm just not sure if you're more focussed on Forth itself and perhaps my
> attempts to emulate the hardware might be off-topic there.
>
> Er.  Except they're off-topic here too, so... um.  Sorry folks. :-)
> --
> Cheers,
> Stuart
>

Re: Prototype of case for planed new computer SAM COUPE 2

[Thomas Harte]

I'm in the US at the minute, being unjustly overpaid. And probably for another 
couple of years.

 On 30 Apr 2015, at 18:25, Aleš Keprt a...@keprt.cz wrote:
 
 I think the NTSC-PAL signal compatibility differs manufacturer to 
 manufacturer. But I wonder why do you use a NTSC display. You live outside of 
 Europe? Or you mean NTSC like a standard 60 Hz computer monitor?
  
  
 From: Thomas Harte
 Sent: Thursday, April 30, 2015 10:18 PM
 To: sam-users@nvg.ntnu.no
 Subject: Re: Prototype of case for planed new computer SAM COUPE 2
  
 With further consideration I'd suggest that the hypothetical hardware 
 LDIR-alike be optionally able to logically invert its output addresses. With 
 suitable adjustments to the inputs, that gives you counting down as well as 
 counting up. So you can also scroll left-to-right!
  
 That stuff all aside, does anybody know anything about the compatibility of 
 PAL machines with modern NTSC flat screens? The one I have otherwise does an 
 excellent job with a composite input, including the off-spec non-interlaced 
 stuff that '80s computers put out, but I've not tried it with a 50Hz or PAL 
 signal. Do manufacturers still bother to differentiate or have economies of 
 scale reduced everything down to a single chip regardless?
  
 It also has component inputs but I've nothing that outputs component video 
 and wouldn't be surprised if it's implemented in such a way as to accept only 
 HDTV signals.
  
 Which is a roundabout way of wondering whether I'd ever be able to use a Sam 
 2 on this side of the Atlantic. Anyone care to speculate? I guess one of 
 those composite/s-video/RGB to HDMI converters might be a smart investment 
 anyway as they're probably only going to get more obscure.
  
 On 29 April 2015 at 08:09, da...@properbastard.co.uk wrote:
 Case looks very good. Discussion is pretty interesting.
 
  
 
 On 29.04.2015 09:34, the wub wrote:
 
 What a great project, your Sam Coupe 2 looks really amazing.  I
 particularly like the spherical feet!
 
 And the Lynx did have at least one good game: Super Skweek! :)
  
 
  
 
  
 -
 Mgr. Aleš Keprt, Ph.D.
 private: a...@keprt.cz, www.keprt.cz
 office: Moravian University College / Moravská vysoká škola Olomouc, 
 ales.ke...@mvso.cz

Re: Prototype of case for planed new computer SAM COUPE 2

[Thomas Harte]

Yeah, it was years ahead of its time. The Gameboy Advance was a decade
later and still primarily for hardware sprites on tile maps.

But I'd still much rather see, say, a simple three-register thing: push
source address, push destination address, push length and it raises the
halt line and then copies that many bytes from source to destination at the
maximum rate (allowing for screen refresh). That's probably even simpler to
implement than hardware sprites, being just the innermost loop. The CPU
still has to do quite a lot but not too much, I think.

Anyway, neither option is really something I consider particularly
essential or even necessarily useful for a 2015 Sam 2. Just things we wish
had been in the 1989 Sam 1.

On Tuesday, 28 April 2015, Aleš Keprt a...@keprt.cz wrote:

 Technically you are correct, but I think you cannot compare the
 professional product of top class technology company like Atari with
 amateur home made product like this Sam Coupe 2. I think even the original
 Sam Coupe was rather a home made product than a professional computer
 hardware on the technology level possible in the 1980's.

 -Původní zpráva- From: Thomas Harte
 Sent: Tuesday, April 28, 2015 1:55 PM
 To: sam-users@nvg.ntnu.no
 Subject: Re: Prototype of case for planed new computer SAM COUPE 2

 True, but both the Lynx and the Sam came out in the same year and the Sam
 was the more expensive of the two. The Lynx gets away with it, I think,
 because it's pushing only an 8kb frame buffer — 160x102 in 4bpp. So divide
 all your mental calculations by three.

 ... though, of course, I wouldn't advocate it if fun games are your real
 objective.

 The Lynx's design is what Needle and Mical did after the Amiga and before
 the 3DO so it's from that lineage of design. The graphics hardware is like
 an Amiga plus in many ways, though a 6502 was all they could fit into the
 mobile transistor budget.

  On 28 Apr 2015, at 07:22, Aleš Keprt a...@keprt.cz wrote:

 AKAIK the hardware sprites are much simpler to implement. I don't know
 Lynx, but the blitter like you described needs uncomparably faster hardware
 than a set of hardware sprites.
 A.

 -Původní zpráva- From: Thomas Harte
 Sent: Tuesday, April 28, 2015 1:12 PM
 To: sam-users@nvg.ntnu.no
 Subject: Re: Prototype of case for planed new computer SAM COUPE 2

 I'm inclined to think the Atari Lynx is the pinnacle of '80s graphics
 chipsets: just a frame buffer and a scaling blitter. No need for all the
 special-case sprites/backgrounds nonsense.

  On 28 Apr 2015, at 06:32, Leslie Anderson lezander...@gmail.com wrote:

 In an ideal world you could have :

 32/8 full colour hardware sprites ...16x16 or 8x8 ? with sprite
 collision detection ?
 Hardware scroll vertical/horizontal
 Increase in Colour palette
 Hardware line interrupts (programmable) to switch palette at a fixed
 number of scan lines ? No need for CPU intervention.

 Even a second Video processor to give superposition, Superimposed video

Re: Prototype of case for planed new computer SAM COUPE 2

[Thomas Harte]

True, but both the Lynx and the Sam came out in the same year and the Sam was 
the more expensive of the two. The Lynx gets away with it, I think, because 
it's pushing only an 8kb frame buffer — 160x102 in 4bpp. So divide all your 
mental calculations by three.

... though, of course, I wouldn't advocate it if fun games are your real 
objective.

The Lynx's design is what Needle and Mical did after the Amiga and before the 
3DO so it's from that lineage of design. The graphics hardware is like an Amiga 
plus in many ways, though a 6502 was all they could fit into the mobile 
transistor budget.

 On 28 Apr 2015, at 07:22, Aleš Keprt a...@keprt.cz wrote:
 
 AKAIK the hardware sprites are much simpler to implement. I don't know Lynx, 
 but the blitter like you described needs uncomparably faster hardware than a 
 set of hardware sprites.
 A.
 
 -Původní zpráva- From: Thomas Harte
 Sent: Tuesday, April 28, 2015 1:12 PM
 To: sam-users@nvg.ntnu.no
 Subject: Re: Prototype of case for planed new computer SAM COUPE 2
 
 I'm inclined to think the Atari Lynx is the pinnacle of '80s graphics 
 chipsets: just a frame buffer and a scaling blitter. No need for all the 
 special-case sprites/backgrounds nonsense.
 
 On 28 Apr 2015, at 06:32, Leslie Anderson lezander...@gmail.com wrote:
 
 In an ideal world you could have :
 
 32/8 full colour hardware sprites ...16x16 or 8x8 ? with sprite collision 
 detection ?
 Hardware scroll vertical/horizontal
 Increase in Colour palette
 Hardware line interrupts (programmable) to switch palette at a fixed number 
 of scan lines ? No need for CPU intervention.
 
 Even a second Video processor to give superposition, Superimposed video. 
 This could be something like a V9938/V9958. though this obviously would mean 
 quite a bit of extra circuitry, but the resulting graphics would be superb, 
 probably surpassing a Commodore AMIGA.
 
 Though this all boils down to someone with the time, brains and means to 
 make it happen !
 
 On 28 April 2015 at 09:28, Andrew Park alp...@ntlworld.com wrote:
 I think hardware sprites would be great, increase in colour palette would 
 be beneficial as long as more colours on screen at once was introduced but 
 given the size of the screen as standard is 24k more colours on screen 
 would mean more memory unless line interrupts were used then this would 
 have speed issues on the cpu, so how could this be used?
 
 
 
 From: owner-sam-us...@nvg.ntnu.no [mailto:owner-sam-us...@nvg.ntnu.no] On 
 Behalf Of Leszek Chmielewski
 Sent: 27 April 2015 22:27
 To: sam-users@nvg.ntnu.no
 Subject: Re: Prototype of case for planed new computer SAM COUPE 2
 
 
 
 I agree. The original (crowdfunding) plans for the new Golden ASIC's 
 involved hardware sprites and palette expansion to 4096, which is enough 
 for most needs, and this as upgrade for the original SAM 1.
 
 LCD
 
 
 
 On Mon, Apr 27, 2015 at 11:20 PM, Aleš Keprt a...@keprt.cz wrote:
 
 I think hardware sprites would be more beneficial than so many colors. If I 
 look to old game cabinets from 80’s, many of them have got excellent games 
 with simple slow CPU’s... but always with hardware sprites=
 
 -
 Mgr. Aleš Keprt, Ph.D.
 private: a...@keprt.cz, www.keprt.cz
 office: Moravian University College / Moravská vysoká škola Olomouc, 
 ales.ke...@mvso.cz 

Re: Prototype of case for planed new computer SAM COUPE 2

[Thomas Harte]

It reflects poorly on me but Spanish isn't one of my languages. What sort of 
machine is it? A genuine hardware compatible or just a Pi-or-whatever in a 
suitable case? How much? When? In what form?

Very exciting.

 On 22 Apr 2015, at 14:59, Andrew Park alp...@ntlworld.com wrote:
 
 Interested to see some more information on this, will it be a DIY sam or 
 produced?
  
 Andy
  
  
 From: owner-sam-us...@nvg.ntnu.no [mailto:owner-sam-us...@nvg.ntnu.no] On 
 Behalf Of Kurt K
 Sent: 22 April 2015 17:34
 To: sam-users@nvg.ntnu.no
 Subject: Re: Prototype of case for planed new computer SAM COUPE 2
  
 Where do we find more information?  I'd love to get one.  I'll have to look 
 closer on Velesoft's website.
 
 On Apr 22, 2015, at 10:50 AM, Leszek Chmielewski retr...@gmail.com wrote:
 
 How much will it cost?
  
 On Wed, Apr 22, 2015 at 5:29 PM, VELESOFT veles...@seznam.cz wrote:
 It's first version of case for planed new computer SAM COUPE 2:
 
 http://velesoft.speccy.cz/other/SAMCASE_6E.JPG
 http://velesoft.speccy.cz/other/SAMCASE_6A.JPG
 http://velesoft.speccy.cz/other/SAMCASE_6D.JPG
 http://velesoft.speccy.cz/other/SAMCASE_6B.JPG
 http://velesoft.speccy.cz/other/SAMCASE_6C.JPG
 http://velesoft.speccy.cz/other/SAMCASE_6G.JPG
 http://velesoft.speccy.cz/other/SAMCASE_6H.JPG
 
 VELESOFT
 
 ---
 Tato zpráva byla zkontrolována na viry programem Avast Antivirus

Re: R: R: R: Hi All Sam Users From Italy!

[Thomas Harte]

So, it’s slender pickings, but everything I seem to have put on disk with 
Samtape and which is also now available from World of Spectrum can be grabbed 
at https://www.dropbox.com/sh/iksl9n0672miyqq/AADxzgPmOUzYC6g6wrRwvSM7a?dl=0

As I said, I no longer have a copy of Samtape, that disk having expired a long 
time ago, so I can’t speak as to the functionality of any of these files. 
Having been a disorganised 10-year old when I had a Sam, it’s very possible 
that some of these aren’t what they say they are or possibly aren’t even 
Samtape files. Good luck!

I was not able to find a single 128k conversion, though I’m sure I had some.
On 29 August 2014 at 08:22:13, Simone Voltolini (simone.voltol...@tin.it) wrote:

I've 30 disks images with 128 conversions + other 18 but I think there will be 
more outside ;)  

Let me gently know, thanks.  









Simone Voltolini  
Via Cavour 1, 46030 San Giorgio di Mantova MN  
Tel/Fax +39 0376 371059  
voip: 0376 1855999 - P. IVA 02048930206  
skype: ranma_simon  


-Messaggio originale-  
Da: owner-sam-us...@nvg.ntnu.no [mailto:owner-sam-us...@nvg.ntnu.no] Per conto 
di Thomas Harte  
Inviato: venerdì 29 agosto 2014 16:46  
A: sam-users@nvg.ntnu.no  
Oggetto: Re: R: R: Hi All Sam Users From Italy!  

I think I had 4 back in the day; couldn't comment on earlier versions. If you 
have the manual, does it comment on the file format? It's bound to be something 
it would be easy to convert .SNA to.  

I think I also had Sam conversions of the 128k versions of Chase HQ and Tetris 
2. I'm unlikely still to have them, but I'll check (and versus World of 
Spectrum too, obviously)...  

 On 29 Aug 2014, at 07:39, Simone Voltolini simone.voltol...@tin.it wrote: 
  
  
 I perfectly know Thomas.  
  
 I have the original Sam Tape 3 version and some images produced with Speccy 
 stuff too.  
  
 But I've read that the version 4 is absolutely the best one.  
  
  
  
  
  
  
  
  
  
 Simone Voltolini  
 Via Cavour 1, 46030 San Giorgio di Mantova MN Tel/Fax +39 0376 371059  
 voip: 0376 1855999 - P. IVA 02048930206  
 skype: ranma_simon  
  
  
 -Messaggio originale-  
 Da: owner-sam-us...@nvg.ntnu.no [mailto:owner-sam-us...@nvg.ntnu.no]  
 Per conto di Thomas Harte  
 Inviato: venerdì 29 agosto 2014 16:08  
 A: sam-users@nvg.ntnu.no  
 Oggetto: Re: R: Hi All Sam Users From Italy!  
  
 This list is strictly legal so nothing can be redistributed unless the 
 original authors have given permission.  
  
 I've got some Samtape snaps of Spectrum software hanging around though; I'll 
 see what's permitted for redistribution on World of Spectrum and get back to 
 you, but probably not until the far end of the weekend. Sadly I think I no 
 longer have Samtape and it explicitly isn't redistributable so I can't test 
 anything.  
  
 On 29 Aug 2014, at 06:55, Simone Voltolini simone.voltol...@tin.it 
 wrote:  
  
 Thanks a lot Wub.  
  
 It was a dream for me to have finally in my hand a Sam Coupè.  
  
 I hope that someone can help me to find Samtape 4 and Kobrahsoft CD2 Tape di 
 Sam Disk drive utilities.  
  
 Best wishes.  
  
  
  
  
  
  
  
  
  
 Simone Voltolini  
 Via Cavour 1, 46030 San Giorgio di Mantova MN Tel/Fax +39 0376 371059  
 voip: 0376 1855999 - P. IVA 02048930206  
 skype: ranma_simon  
  
  
 -Messaggio originale-  
 Da: owner-sam-us...@nvg.ntnu.no [mailto:owner-sam-us...@nvg.ntnu.no]  
 Per conto di the wub  
 Inviato: venerdì 29 agosto 2014 15:49  
 A: sam-users@nvg.ntnu.no  
 Oggetto: Re: Hi All Sam Users From Italy!  
  
 Hi and welcome to the Sam scene! :)  
  
 You made a great choice, the Sam has some excellent software and is the 
 nicest way to play spectrum games on real hardware too!  
  
 Have fun!  
  
 Rob.  
  

Re: R: R: R: Hi All Sam Users From Italy!

[Thomas Harte]

Cool. And if you have any of the games on there already, it might be 
interesting to do a differential comparison of the files — they’ll be mostly 
the 48k of memory and that’ll be mostly the same, so with some educated 
guesswork it might be possible to derive the .LRM file format and write a 
conversion tool between it and .SNA. Then you could use any game you can find 
online.

… though SC_Speclone would probably be the smarter thing: it’s free for 
redistribution and can load Plus D snapshot files, which someone’s bound 
already to have figured out.
On 30 August 2014 at 15:26:29, Simone Voltolini (simone.voltol...@tin.it) wrote:

Thanks Thomas, I will test it and let you know.


Kora Sistemi Informatici S.r.l.

Il giorno 31/ago/2014, alle ore 00:17, Thomas Harte tomh.retros...@gmail.com 
ha scritto:

So, it’s slender pickings, but everything I seem to have put on disk with 
Samtape and which is also now available from World of Spectrum can be grabbed 
at https://www.dropbox.com/sh/iksl9n0672miyqq/AADxzgPmOUzYC6g6wrRwvSM7a?dl=0

As I said, I no longer have a copy of Samtape, that disk having expired a long 
time ago, so I can’t speak as to the functionality of any of these files. 
Having been a disorganised 10-year old when I had a Sam, it’s very possible 
that some of these aren’t what they say they are or possibly aren’t even 
Samtape files. Good luck!

I was not able to find a single 128k conversion, though I’m sure I had some.
On 29 August 2014 at 08:22:13, Simone Voltolini (simone.voltol...@tin.it) wrote:

I've 30 disks images with 128 conversions + other 18 but I think there will be 
more outside ;)

Let me gently know, thanks.









Simone Voltolini
Via Cavour 1, 46030 San Giorgio di Mantova MN
Tel/Fax +39 0376 371059
voip: 0376 1855999 - P. IVA 02048930206
skype: ranma_simon


-Messaggio originale-
Da: owner-sam-us...@nvg.ntnu.no [mailto:owner-sam-us...@nvg.ntnu.no] Per conto 
di Thomas Harte
Inviato: venerdì 29 agosto 2014 16:46
A: sam-users@nvg.ntnu.no
Oggetto: Re: R: R: Hi All Sam Users From Italy!

I think I had 4 back in the day; couldn't comment on earlier versions. If you 
have the manual, does it comment on the file format? It's bound to be something 
it would be easy to convert .SNA to.

I think I also had Sam conversions of the 128k versions of Chase HQ and Tetris 
2. I'm unlikely still to have them, but I'll check (and versus World of 
Spectrum too, obviously)...

 On 29 Aug 2014, at 07:39, Simone Voltolini simone.voltol...@tin.it wrote:

 I perfectly know Thomas.

 I have the original Sam Tape 3 version and some images produced with Speccy 
 stuff too.

 But I've read that the version 4 is absolutely the best one.









 Simone Voltolini
 Via Cavour 1, 46030 San Giorgio di Mantova MN Tel/Fax +39 0376 371059
 voip: 0376 1855999 - P. IVA 02048930206
 skype: ranma_simon


 -Messaggio originale-
 Da: owner-sam-us...@nvg.ntnu.no [mailto:owner=

Re: R: Hi All Sam Users From Italy!

[Thomas Harte]

This list is strictly legal so nothing can be redistributed unless the original 
authors have given permission.

I've got some Samtape snaps of Spectrum software hanging around though; I'll 
see what's permitted for redistribution on World of Spectrum and get back to 
you, but probably not until the far end of the weekend. Sadly I think I no 
longer have Samtape and it explicitly isn't redistributable so I can't test 
anything.

 On 29 Aug 2014, at 06:55, Simone Voltolini simone.voltol...@tin.it wrote:
 
 Thanks a lot Wub.
 
 It was a dream for me to have finally in my hand a Sam Coupè.
 
 I hope that someone can help me to find Samtape 4 and Kobrahsoft CD2 Tape di 
 Sam Disk drive utilities.
 
 Best wishes.
 
 
 
 
 
 
 
 
 
 Simone Voltolini
 Via Cavour 1, 46030 San Giorgio di Mantova MN
 Tel/Fax +39 0376 371059
 voip: 0376 1855999 - P. IVA 02048930206
 skype: ranma_simon
 
 
 -Messaggio originale-
 Da: owner-sam-us...@nvg.ntnu.no [mailto:owner-sam-us...@nvg.ntnu.no] Per 
 conto di the wub
 Inviato: venerdì 29 agosto 2014 15:49
 A: sam-users@nvg.ntnu.no
 Oggetto: Re: Hi All Sam Users From Italy!
 
 Hi and welcome to the Sam scene! :)
 
 You made a great choice, the Sam has some excellent software and is the 
 nicest way to play spectrum games on real hardware too!
 
 Have fun!
 
 Rob.
 

Re: R: R: Hi All Sam Users From Italy!

[Thomas Harte]

I think I had 4 back in the day; couldn't comment on earlier versions. If you 
have the manual, does it comment on the file format? It's bound to be something 
it would be easy to convert .SNA to.

I think I also had Sam conversions of the 128k versions of Chase HQ and Tetris 
2. I'm unlikely still to have them, but I'll check (and versus World of 
Spectrum too, obviously)...

 On 29 Aug 2014, at 07:39, Simone Voltolini simone.voltol...@tin.it wrote:
 
 I perfectly know Thomas.
 
 I have the original Sam Tape 3 version and some images produced with Speccy 
 stuff too.
 
 But I've read that the version 4 is absolutely the best one.
 
 
 
 
 
 
 
 
 
 Simone Voltolini
 Via Cavour 1, 46030 San Giorgio di Mantova MN
 Tel/Fax +39 0376 371059
 voip: 0376 1855999 - P. IVA 02048930206
 skype: ranma_simon
 
 
 -Messaggio originale-
 Da: owner-sam-us...@nvg.ntnu.no [mailto:owner-sam-us...@nvg.ntnu.no] Per 
 conto di Thomas Harte
 Inviato: venerdì 29 agosto 2014 16:08
 A: sam-users@nvg.ntnu.no
 Oggetto: Re: R: Hi All Sam Users From Italy!
 
 This list is strictly legal so nothing can be redistributed unless the 
 original authors have given permission.
 
 I've got some Samtape snaps of Spectrum software hanging around though; I'll 
 see what's permitted for redistribution on World of Spectrum and get back to 
 you, but probably not until the far end of the weekend. Sadly I think I no 
 longer have Samtape and it explicitly isn't redistributable so I can't test 
 anything.
 
 On 29 Aug 2014, at 06:55, Simone Voltolini simone.voltol...@tin.it wrote:
 
 Thanks a lot Wub.
 
 It was a dream for me to have finally in my hand a Sam Coupè.
 
 I hope that someone can help me to find Samtape 4 and Kobrahsoft CD2 Tape di 
 Sam Disk drive utilities.
 
 Best wishes.
 
 
 
 
 
 
 
 
 
 Simone Voltolini
 Via Cavour 1, 46030 San Giorgio di Mantova MN Tel/Fax +39 0376 371059
 voip: 0376 1855999 - P. IVA 02048930206
 skype: ranma_simon
 
 
 -Messaggio originale-
 Da: owner-sam-us...@nvg.ntnu.no [mailto:owner-sam-us...@nvg.ntnu.no] 
 Per conto di the wub
 Inviato: venerdì 29 agosto 2014 15:49
 A: sam-users@nvg.ntnu.no
 Oggetto: Re: Hi All Sam Users From Italy!
 
 Hi and welcome to the Sam scene! :)
 
 You made a great choice, the Sam has some excellent software and is the 
 nicest way to play spectrum games on real hardware too!
 
 Have fun!
 
 Rob.
 

Re: Bug in game Oh No! More Lemmings

[Thomas Harte]

I didn’t own either of the Lemmings titles back in the day so this is quite 
exciting news. But is there a trick to getting Oh No More Lemmings to work? It 
doesn’t boot on its own and performing a disk swap from the Lemmings title 
screen doesn’t seem to get me anywhere...

On 17 Aug 2014, at 10:43, Colin Piggot qua...@clara.net wrote:

 the wub wrote:
 Really glad to hear that I was probably wrong,  I'd seen this before
 and so leapt to a conclusion. :)
 
 Chris White had granted permission for Prince of Persia, Lemmings and Oh No 
 More Lemmings and they are up on World of Sam for download.
 
 http://www.worldofsam.org/node/403
 
 From Fred 56, the code for Crazy - 4 is: MFMLFKID
 
 Colin
 =
 Quazar : Hardware, Software, Spares and Repairs for the SAM Coupé
 1995-2014 - Celebrating 20 Years of developing for the SAM Coupé
 Website: www.samcoupe.comTwitter: @QuazarSamCoupe
 

Re: Retro shows and Sam's 25th birthday

[Thomas Harte]

I found this thread on the Retro Gamer site, 'Upcoming Retro Gaming/Classic 
Computing events': 
http://www.retrogamer.net/forum/viewtopic.php?f=6t=17231sid=c1d3438d991661ad1afa22f622737505start=345

Nobody seems to have updated the sticky post at the top with anything recent 
but if you skip to the last few pages you’ll see a few scheduled for the 
future. Of those the two that seem least focussed on pinball and arcade 
machines seem to be:

Retro Mania 2
Wickford Community Centre
Market Rd, Wickford, ESSEX, SS12 0AG
22nd - 23rd MARCH 2014
https://www.facebook.com/events/135819333286758/

Revival 2014 […] will now be held on the 9th and 10th August 2014 (in 
Wolverhampton)
http://www.revivalretroevents.com/index.php/component/vikevents/?task=vieweventitid=3

I currently don’t believe I can make either so that’s almost all I have to say 
about that. Otherwise I would suggest Revival as it’s (i) more than a month 
away; and (ii) much closer to the birthday. Also they’re promising “a huge 
selection of competitive traders” which strongly implies a Sam stall could be 
rented at worst.


On 27 Feb 2014, at 10:11, the wub the...@gmail.com wrote:

 definitely interested, would be great to meet you guys!
 
 
 On Wed, Feb 26, 2014 at 9:47 PM, da...@properbastard.co.uk wrote:
 Quoting Ian Spencer i...@spencerweb.net:
 
 No quite Stefan I also live in Germany (near Köln) and have had a sam since 
 the very beginning. I now have two, though these days I usually use the 
 emulator.
 
 Ian
 
 
 Cologne is a nice place indeed - been there a couple of times with the German 
 FGTH Fans.
 
 Perhaps it's possible to arrange a UK based one and a German one? :)
 
 Wonder what Tarquin's doing these days?
 
 

Re: Retro shows and Sam's 25th birthday

[Thomas Harte]

How is Germany for foreigners?

Maybe what we should do is contact someone like the Museum of Computing, which 
obviously isn’t a conference space but often hosts lectures, suggest that the 
Sam is an interesting topic and ask if we can use whatever they have as lecture 
space for an evening? Maybe I’m aiming too high but it’s surely an interesting 
story even for an outsider: what employees of Sinclair did next, how the 
British computer industry ran out of steam? Then if we happen to combine that 
with a detailed discussion of the software and so on, so be it?

On 25 Feb 2014, at 10:02, Ian Spencer i...@spencerweb.net wrote:

 No quite Stefan I also live in Germany (near Köln) and have had a sam since 
 the very beginning. I now have two, though these days I usually use the 
 emulator.
 
 Ian
 
 Am 25.02.2014 04:46, schrieb stefan_schomb...@agilent.com:
 I would join as well, if it does no collide with any work appointments. You 
 can imagine how desperate I am for a such a meeting – the SAM is too exotic 
 for most Germans, so I am a lone warrior over here… J
  
 From: owner-sam-us...@nvg.ntnu.no [mailto:owner-sam-us...@nvg.ntnu.no] On 
 Behalf Of Thomas Harte
 Sent: Monday, February 24, 2014 11:54 PM
 To: sam-users@nvg.ntnu.no
 Subject: Re: Retro shows and Sam's 25th birthday
  
 How much does it cost to book a venue anyway? We could just organise one 
 ourselves.
  
 On 24 Feb 2014, at 22:25, Mike Nicholas m...@euroasic.com wrote:
 
 
 I too would be interested.  
 SAM was a huge part of my childhood and kept me out of mischief :-)
 
 On 24 February 2014, Thomas Harte tomh.retros...@gmail.com wrote:
 
 I’ve never been to one but would definitely try to make some effort if 
 something like this were arranged. There’s a 90% chance it’d be while I’m 
 out of the country but it’d be a good excuse to write something.
 
 On 24 Feb 2014, at 13:42, Andrew Collier and...@intensity.org.uk wrote:
 
 Hi,
 
 I guess the Sam's 25th birthday is coming up this year.
 
 I was wondering anybody regularly goes to any of the retro computer shows 
 which happen from time to time, and whether there would be any interest from 
 sam-users generally to meet up at one of them? If there's a good one towards 
 the end of the year we could perhaps arrange a few Sam related stands, and 
 'adopt' it as a Sam's 25th anniversary event?
 
 Andrew
 
  
  
 
 

Re: Retro shows and Sam's 25th birthday

[Thomas Harte]

I’ve never been to one but would definitely try to make some effort if 
something like this were arranged. There’s a 90% chance it’d be while I’m out 
of the country but it’d be a good excuse to write something.

On 24 Feb 2014, at 13:42, Andrew Collier and...@intensity.org.uk wrote:

 Hi,
 
 I guess the Sam's 25th birthday is coming up this year.
 
 I was wondering anybody regularly goes to any of the retro computer shows 
 which happen from time to time, and whether there would be any interest from 
 sam-users generally to meet up at one of them? If there's a good one towards 
 the end of the year we could perhaps arrange a few Sam related stands, and 
 'adopt' it as a Sam's 25th anniversary event?
 
 Andrew
 

Re: SimCoupe / Trinity

[Thomas Harte]

How do the economics work out on this sort of project? I've seen, for
example, $8000 raised on KickStarter for a CP/M machine —
http://www.kickstarter.com/projects/2057605091/p112-single-board-computer-kit—
but that was just for a new run of a fully designed machine that had
been
produced in the past and that is in many respects less complicated than a
Sam (no video output, for example) and definitely an easier target to hit
(eg, no specific bus timing is required).

I feel that if you're going to produce a new Sam, whether upgraded or
merely shrunk down, the way to make it an appealing product is to package
it in its entirety into a thumb stick with, say, HDMI and USB ports for a
TV and an optional keyboard, and either bundle every piece of software you
can license onto a built-in ROM or give us an SD slot and hope that the
market provides. Actually, Bluetooth is so cheap nowadays, maybe don't even
bother with the USB port. But then you get to: why not just do it in
software and install it on last year's mobile phone?


On 3 May 2013 12:00, david brant davidcbr...@yahoo.com wrote:

 Yes but Bob wanted us to buy a ROM thing to sort out BASIC which I thought
 was pointless. Most of the time it works fine unless you write a very long
 program or use lots of DIM in it. But I've never written such big programs.

 If he come up with new hardware he may got better input or at listen to us
 coders

 On 3 May 2013, at 19:49, Gavin Smith wrote:

 A super SAM-type project has been talked about since Bob Brenchley kept us
 all going about his SamSon idea! If it's ever to happen, it will take
 someone to do it off their own back and just see it through because most of
 us on this list will be too skeptical and jaded to lend much support! I
 think such a project might even have had a wider market if it had been done
 years ago, before the Raspberry Pi.

 Colin has already got a 20+MHz Sam working with his prototype mayhem
 accelerator and the last time he mentioned it in his mag, he was looking at
 CPLD to reduce logic. He has also hinted in SR that a special issue would
 cover a secret project he was working on so maybe it's related to a Quazar
 Super Sam?

 Sent from my iPad

 On 3 May 2013, at 19:30, Leslie Anderson lezander...@gmail.com wrote:

 Would anybody buy it ??? How many SAM users would want one ?? And I'd have
 to do costings to see how much the final unit would cost ! But if there are
 people interested just let me know.


 On 3 May 2013 19:13, david brant davidcbr...@yahoo.com wrote:

 Well what you waiting for if it that easy! No idea with hardware myself.

 On 3 May 2013, at 18:46, Leslie Anderson wrote:

  Perhaps it's time for someone to design a NEW SAM COUPE. SAM II + or
  Super SAM.  What was done on the original SAM in dozen of chips could
 now
  be done in about 8 distinctive ICs Then everyone could have a Super
 SAM!
 
  Z84C0020   Z80 CPU.. 20MHz
  K6T4008 512Kx 8 bit SRAM
  W27C010128K EEPROM
  MAX EPM7512   CPLD  512 macrocells
  SAA1099   Sound   (PSG)
 
 
  The MAX EPM7512 would be used to generate video, perform I/O, Memory
  Decoding etc. The original ZX Spectrum ULA used about 144 macrocells, so
  512 should be enough.
 
 
  On 3 May 2013 18:03, david brant davidcbr...@yahoo.com wrote:
 
 
  How about some means that you need the hardware to work on the PC,Mac
 etc

Re: SimCoupe / Trinity

[Thomas Harte]

Surely design and testing would be the real cost? Plus finding sufficiently
many people to justify a PCB run?

I'm way out of my depth here, correct me if I'm wrong. I read the Spectrum
ULA book so suddenly I feel like a genius.


On 3 May 2013 13:25, Leslie Anderson lezander...@gmail.com wrote:

 Costings for a 'SAM Plus' would not be too high as the legacy  ICs are
 quite cheap :

 Z84C0020VEC or PEC   about £1.50
 K6T4008   about  £2.70
 W27C512 or W27C010   about   £0.60
 EPM7512  Expensive £20
 SAA1099  about £1.50
 Plus :
 AY-3-8910   PSG (Spectrum)about  £1.75
 V9958+VRAM second VDP about £5

 Miscellaneous ICs, 7805,DACs etc   about £5.0

 Resistors capacitors etc  £5.0

 Double sided board PCB approx £7.50-£10  multilayer board ???

 Total Cost :  £55 ??

 To design would take about six months or so...How many would sell ,
 even for cost ??

 The real question is how many would be ordered and it is worth the effort
 for such a small number ?







 On 3 May 2013 20:00, david brant davidcbr...@yahoo.com wrote:

 Yes but Bob wanted us to buy a ROM thing to sort out BASIC which I
 thought was pointless. Most of the time it works fine unless you write a
 very long program or use lots of DIM in it. But I've never written such big
 programs.

 If he come up with new hardware he may got better input or at listen to
 us coders

 On 3 May 2013, at 19:49, Gavin Smith wrote:

 A super SAM-type project has been talked about since Bob Brenchley kept
 us all going about his SamSon idea! If it's ever to happen, it will take
 someone to do it off their own back and just see it through because most of
 us on this list will be too skeptical and jaded to lend much support! I
 think such a project might even have had a wider market if it had been done
 years ago, before the Raspberry Pi.

 Colin has already got a 20+MHz Sam working with his prototype mayhem
 accelerator and the last time he mentioned it in his mag, he was looking at
 CPLD to reduce logic. He has also hinted in SR that a special issue would
 cover a secret project he was working on so maybe it's related to a Quazar
 Super Sam?

 Sent from my iPad

 On 3 May 2013, at 19:30, Leslie Anderson lezander...@gmail.com wrote:

 Would anybody buy it ??? How many SAM users would want one ?? And I'd
 have to do costings to see how much the final unit would cost ! But if
 there are people interested just let me know.


 On 3 May 2013 19:13, david brant davidcbr...@yahoo.com wrote:

 Well what you waiting for if it that easy! No idea with hardware myself

Re: disassembling SamForth

[Thomas Harte]

As a slightly younger person (relative to the mailing list for a niche 80s
micro, anyway) I'd no concept of the syntax or semantics of Forth until I
read your site and a few sources on from that.

Would it be fair to describe Forth as the procedural analogue of Smalltalk?
I'm thinking specifically about strict left-to-right evaluation, words
having meaning only by definition and runtime components doing the things
that are usually specialised syntax like branches and loops. Both are also
classically interactive environments with live feedback from which entire
OSes sprung.

Smalltalk is similarly typeless which I guess leads to the main distinction
— that words are looked at dynamically depending on preceding words rather
than statically and statelessly from a global store to create threaded code

Re: text spooling

[Thomas Harte]

On 16 November 2012 10:38, Simon Owen simon.o...@simcoupe.org wrote:
 For the other ports I was planning to use iconv to do the main
 transliteration step.  Under Linux iconv (part of libc-bin) appears to
 include the support I'm after.  Mac OS X is still using the traditional
 libiconv, which gives strange results with the accents separated out
 (coupé - coup'e).  If I can't find a quick and easy solution for
 that I'll just drop transliteration support.  I'd rather spend my
 SimCoupe development time on emulation, not text conversion!

What's your policy on native code? I ran a quick test with:

NSString *testString = @Coupé;
char terminator = '\0';
NSMutableData *asciiData = [[[testString
dataUsingEncoding:NSASCIIStringEncoding allowLossyConversion:YES]
mutableCopy] autorelease];
[asciiData appendBytes:terminator length:1];
NSLog(@%@ %s, testString, [asciiData bytes]);

Output was: Coupé Coupe

cStringUsingEncoding: directly on the string didn't do the job sadly
since it doesn't permit a lossy conversion and there's no direct
method for a lossy conversion with a C-style terminator.

Re: Accessing Sam formatted disks through a USB floppy drive

[Thomas Harte]

Well, I've got a Kryoflux now, connected to the cheapest standard PC
floppy drive that I could find on eBay, and it's working really well.
The supplied software has a GUI (if you're willing to install Java,
anyway; pleasingly it is OS X v10.8 compatible) and one of the output
options is a raw MFM sector image, which ends up being a .MGT in Sam
emulator terms. So the process is just insert disk, click 'start',
adjust a file extension and repeat. It takes a bit more than one and a
half minutes to do a good disk, obviously more if it ends up retrying
sectors.

My disks have been in my mother's (standalone, sheltered but
uninsulated) garage for the last six years but were in a house for the
10–15 years before that and I'm probably getting an 80% read success
rate. Total cost for interface and drive was about £100 but I've
recovered lots of work by myself as a child so it was easily worth it;
this is the first time I've had any means of imaging disks at all so
I've not had an opportunity to rescue anything before.

Definitely recommended for anybody else in a similar situation.

On 24 July 2012 23:20, Thomas Harte tomh.retros...@gmail.com wrote:
 I've ordered one so I'll report on my findings when I have some.

 Sadly I'll just be preserving some of my own early creative work — I
 was about 11 at the time so it's nothing that would be of interest to
 anybody else. I'm not going to have anything of interest that's legal
 to distribute that isn't already freely available.

 On 24 July 2012 09:57, Leszek Chmielewski retr...@gmail.com wrote:
 No, but, read here:
 http://www.softpres.org/news:2010-02-18
 Looks like it supports SAM Coupé.
 I only do not know if it saves in MGT format.

 Am 23.07.2012 18:04, schrieb Thomas Harte:

 Being back in the UK for maybe three weeks and having uncovered some old
 floppies, and having no access to a PC with a floppy drive controller, did
 anyone try the Kyroflux route?

 On Thursday, 28 July 2011, Leszek Chmielewski wrote:



  You're welcome, glad to hear you got your data back. Most of my Sam
  disks
  are unreadable; whether my original Sam was close to the edge of spec
  or
  whether the disks have just degraded over time I'm unsure.
 
  And congrats on the new arrival! Sell the Sam and invest in some
  heavy-duty
  earplugs :)
 
  Geoff
 

 It depends much on the disc drive. I had here some SAM discs which were
 unreadable on PC or SAM, but a very good Drive I have for my +D was still
 able to copy it to new formated disc, and I was able to copy almost all
 files on my PC. The fail rate is very low. If the files are valuable for
 you, I can try to recover them.

 Leszek

Re: Accessing Sam formatted disks through a USB floppy drive

[Thomas Harte]

I've ordered one so I'll report on my findings when I have some.

Sadly I'll just be preserving some of my own early creative work — I
was about 11 at the time so it's nothing that would be of interest to
anybody else. I'm not going to have anything of interest that's legal
to distribute that isn't already freely available.

On 24 July 2012 09:57, Leszek Chmielewski retr...@gmail.com wrote:
 No, but, read here:
 http://www.softpres.org/news:2010-02-18
 Looks like it supports SAM Coupé.
 I only do not know if it saves in MGT format.

 Am 23.07.2012 18:04, schrieb Thomas Harte:

 Being back in the UK for maybe three weeks and having uncovered some old
 floppies, and having no access to a PC with a floppy drive controller, did
 anyone try the Kyroflux route?

 On Thursday, 28 July 2011, Leszek Chmielewski wrote:



  You're welcome, glad to hear you got your data back. Most of my Sam
  disks
  are unreadable; whether my original Sam was close to the edge of spec
  or
  whether the disks have just degraded over time I'm unsure.
 
  And congrats on the new arrival! Sell the Sam and invest in some
  heavy-duty
  earplugs :)
 
  Geoff
 

 It depends much on the disc drive. I had here some SAM discs which were
 unreadable on PC or SAM, but a very good Drive I have for my +D was still
 able to copy it to new formated disc, and I was able to copy almost all
 files on my PC. The fail rate is very low. If the files are valuable for
 you, I can try to recover them.

 Leszek

Re: Accessing Sam formatted disks through a USB floppy drive

[Thomas Harte]

Being back in the UK for maybe three weeks and having uncovered some old
floppies, and having no access to a PC with a floppy drive controller, did
anyone try the Kyroflux route?

On Thursday, 28 July 2011, Leszek Chmielewski wrote:



  You're welcome, glad to hear you got your data back. Most of my Sam
 disks
  are unreadable; whether my original Sam was close to the edge of spec or
  whether the disks have just degraded over time I'm unsure.
 
  And congrats on the new arrival! Sell the Sam and invest in some
 heavy-duty
  earplugs :)
 
  Geoff
 

 It depends much on the disc drive. I had here some SAM discs which were
 unreadable on PC or SAM, but a very good Drive I have for my +D was still
 able to copy it to new formated disc, and I was able to copy almost all
 files on my PC. The fail rate is very low. If the files are valuable for
 you, I can try to recover them.

 Leszek

Re: Good resources for learning about the ASIC?

[Thomas Harte]

My only ASIC has exactly the same fault. Frustratingly it developed it
on a Sam I'd bought from eBay only about four months before to replace
the childhood one that's now long lost. That was about three or four
years and I paid something like £100; looking now the two available
seem to be £500 and £700, though neither appears to be moving at those
prices. Is that really how much I should expect to pay if I ever need
a third?

On 12 June 2012 08:51, Leszek Chmielewski retr...@gmail.com wrote:
 I have a faulty ASIC, which displays no BRIGHT signal, so only 64 colours
 available. But I need a working ASIC first, before I can donate mine.

 LCD

 Am 10.06.2012 22:52, schrieb Thomas Harte:

 Maybe we should get some samples sent into the guys at visual6502.org
 who, despite the name, are attempting to image large swathes of old 8
 bit ICs. See http://visual6502.org/donate_hw.html — they seem fine
 with broken hardware so does anybody have any faulty ASICs? Or spares?
 Possibly even just for sale rather than donation?

 On 10 June 2012 08:02, Adrian Brownadr...@apbcomputerservices.co.uk
  wrote:

 A nice pdf of the logic gate layout would be nice ... ;)

 -Original Message-
 From: owner-sam-us...@nvg.ntnu.no [mailto:owner-sam-us...@nvg.ntnu.no]
 On Behalf Of Tommo H
 Sent: 10 June 2012 04:31
 To: sam-users@nvg.ntnu.no
 Subject: Good resources for learning about the ASIC?

 I'm currently partway through The ZX Spectrum ULA: How To Design a
 Microcomputer, which is the book partly researched by photographing and
 reconstructing the exact IC layout of the Spectrum's ULA. So it goes
 into a lot of detail about how ICs were produced in general, the nature
 of ULAs, the Spectrum's design constraints, how they therefore ended up
 laying things out and all that sort of stuff. As someone who has
 previously looked no lower than product data sheets it's fascinating.

 Does anyone know of any similar sort of details about the Sam's ASIC?
 Presumably it's a similar process - application-specific interconnects
 added to a generic, previously manufactured base - but benefitting from
 seven years of advances in density? Though the Sam's design process
 seems to have been quite extended, so maybe they used some other
 process?

 I guess nobody has the resources to have photographed one but what
 documentation do we have? Google's not turning much up.

Re: Good resources for learning about the ASIC?

[Thomas Harte]

Maybe we should get some samples sent into the guys at visual6502.org
who, despite the name, are attempting to image large swathes of old 8
bit ICs. See http://visual6502.org/donate_hw.html — they seem fine
with broken hardware so does anybody have any faulty ASICs? Or spares?
Possibly even just for sale rather than donation?

On 10 June 2012 08:02, Adrian Brown adr...@apbcomputerservices.co.uk wrote:
 A nice pdf of the logic gate layout would be nice ... ;)

 -Original Message-
 From: owner-sam-us...@nvg.ntnu.no [mailto:owner-sam-us...@nvg.ntnu.no]
 On Behalf Of Tommo H
 Sent: 10 June 2012 04:31
 To: sam-users@nvg.ntnu.no
 Subject: Good resources for learning about the ASIC?

 I'm currently partway through The ZX Spectrum ULA: How To Design a
 Microcomputer, which is the book partly researched by photographing and
 reconstructing the exact IC layout of the Spectrum's ULA. So it goes
 into a lot of detail about how ICs were produced in general, the nature
 of ULAs, the Spectrum's design constraints, how they therefore ended up
 laying things out and all that sort of stuff. As someone who has
 previously looked no lower than product data sheets it's fascinating.

 Does anyone know of any similar sort of details about the Sam's ASIC?
 Presumably it's a similar process - application-specific interconnects
 added to a generic, previously manufactured base - but benefitting from
 seven years of advances in density? Though the Sam's design process
 seems to have been quite extended, so maybe they used some other
 process?

 I guess nobody has the resources to have photographed one but what
 documentation do we have? Google's not turning much up.

Re: BorderTron 3000 - SAM Coupe Edition

[Thomas Harte]

On vaguely these lines, is there any hope of an open source version?
It'd be nice to add a native interface to it, FireMonkey having issues
as you describe, and I'd also like to tie it in with the little tool
I've written for compiling sprites (the shared palette being a reason
to integrate the things). It'd be nice to be able to import PNGs too,
which would probably be about ten lines if I can just use the built-in
Cocoa stuff but I assume would be bucketloads of effort to do in a
cross-platform manner, having to build and link to libpng, etc?

On 6 June 2012 07:59, Simon Owen simon.o...@simcoupe.org wrote:
 On 6 Jun 2012, at 14:50, Chris Cowley wrote:
 I did think about limiting the editable area, but then SimCoupe has that 
 nice View Complete Border option and I
 thought if I restricted it too much, somebody would say Well, it'd be nice 
 if it let you draw in the overscan area :)

 Complete border isn't an authentic feature, but it does help with aligning 
 timing-sensitive code like yours.  The default view area is balanced for 
 normal use, but you lose some lines from top and bottom.  TV-visible adds 
 those back, and is needed to see the top border scroller above Lyra 3's 
 bouncing ball.  TV-visible combined with the 5:4 display ratio option give 
 something that more closely resembles real SAM TV output, though on Vista and 
 Win7 it'll look a bit blocky I finish merging in the new D3D support

Re: New SAM Game: The Lost Disks of SAM

[Thomas Harte]

I agree with Rob and with the other comments; and I'll add that the
slow colouring in of the character to represent lives is a really neat
touch. I'm a bit confused about what the enter key is meant to do on
the info screen though — it seems to redefine black?

On 31 May 2012 13:31, the wub the...@gmail.com wrote:
 What a great game!  The presentation is outstanding, you really have a
 nice style graphically!  I like the infinite lives/quick restart as it
 makes for a very compulsive, this time I'll do it kind of feeling..

 The fact you did this in a month makes you some kind of coding legend!  :)

 Rob.

Re: Quick attempt at a scroller

[Thomas Harte]

I've gone with compiled sprites, and decided to ignore sub-byte
masking, at least for now. That gave me 18 or 19 sprites until I wrote
code to erase them afterwards, which cuts it to a measly 3. Suffice to
say, I'm going to look into other approaches for that step; it's
taking something like 6.5 times as long as drawing them in the first
place.

Anyway: http://www.clocksignal.com/dropbox/scroller-with-three-sprites.dsk

On 19/05/2012, da...@properbastard.co.uk da...@properbastard.co.uk wrote:
 Quoting Balor Price toberm...@cookingcircle.co.uk:

 Aha you flatter me I'm not /that/ old :)  (okay I'm 36)  Yes indeed
 it is Splitting Images - it's another puzzler without any huge
 technical challenges, so I know I'm working within my comfort zone.
 I hadn't planned on making any changes with the personalities, but
 there are a couple of people who aren't immediately obvious, the
 speccy's version of Mick Jagger was terrible!

 I'd agree with Si on this one - unless you totally optimise each
 sprite you aren't looking at many.  But there's masses of memory in
 the SAM so unless you're doing it to squash into memory-resident
 megademo, why not use that memory?  There's often a direct trade-off
 of memory-for-speed (eg unrolling loops, making several specialised
 copies of routines) so go for it.

 Howard


 Besides - if you needed to - it's always perhaps possible to load a
 few random ones from disk... :)

Re: Quick attempt at a scroller

[Thomas Harte]

That's really encouraging; I'm now obsessed with getting a complete
game working at 50Hz and in that context I think even just two or
three sprites would do it. The arbitrary 40% came from what was left
over in the current demo but it strikes me it's also very close to the
amount of time between line 192 and the next line 1 so setting a firm
limit in that range resolves all potential concerns about sprite
flicker (well, until I end up having to display a different three of
the four sprites I really want each frame, or whatever).

And once I have something working along those lines I can start seeing
how well the scrolling holds up with more realistic map data. I've a
few more optimisation ideas either way.

On 18 May 2012 09:46, Simon Owen simon.o...@simcoupe.org wrote:
 On 18 May 2012, at 00:56, Tommo H wrote:
 If I have, say, 40% of a frame to spend on it, how many sprites, and how
 large, is it realistic to expect to be able to draw and un-draw?

 Maybe around 4-5 sprites of 16x16 pixels?  IIRC my Pac-Man emulator has about 
 half a frame to draw 6 sprites of 12x12, plus a couple of background tiles, 
 including save/mask/draw/restore.  For an extra boost perhaps generate the 
 sprite drawing code with knowledge of the data (like Chris did in SAM 
 Defender) — bonus points if you prepare that at runtime.

 It's nice to have some fresh on-topic content to read, so keep posting!

 Si

Re: Quick attempt at a scroller

[Thomas Harte]

Apologies to all; I don't mean to treat this list as my own personal
development blog. However, here's a rock steady 50Hz, full-screen
rendition:

http://www.clocksignal.com/dropbox/scroller-fullscreen-50Hz.dsk

There are two versions on there and some quick relevant notes. Takeaways:

• the border masking is overdraw and I'd rather fix the problem by
just not drawing incorrectly in the first place;
• that being the case, I've only properly profiled the unmasked
version, and found it takes no more than 60% of the available CPU time
per frame in its current state.


On 15 May 2012 12:39,  war...@wdlee.co.uk wrote:
 It's very cool to see scrolling that quick and smooth. :-) We just need
 someone to use it in a game now!!


 Quoting David Sanders dsuzukisand...@gmail.com:

 On 15 May 2012 11:32, Thomas Harte tomh.retros...@gmail.com wrote:

 Or, more likely, the sad realisation that I can't scale the thing to a
 proper game is fast approaching...

 For the record, this is it mostly at 25fps, running (essentially) full
 screen with black guttering to hide the edge jittering of yesterday:

 Indeed, but we can dream eh?


 That is indeed some of the smoothest, fastest full-screen scrolling I've
 seen on the Coupé to date though :-)

Re: Quick attempt at a scroller

[Thomas Harte]

Or, more likely, the sad realisation that I can't scale the thing to a
proper game is fast approaching...

For the record, this is it mostly at 25fps, running (essentially) full
screen with black guttering to hide the edge jittering of yesterday:

http://www.clocksignal.com/dropbox/scroller-big.dsk

It occasionally — and very obviously — leaps up to 50fps, having no
frame rate compensation mechanisms whatsoever.

I'm about 80% confident I can boost the speed to a reasonably constant
50fps, to drop to a constant 25fps with sprites and logic, for a
simple enough game.

On 15 May 2012 08:02, David Sanders dsuzukisand...@gmail.com wrote:
 On 15 May 2012 01:42, Tommo H tomh.retros...@gmail.com wrote:

 I think it'd be nice to go full screen and properly clipped one way or
 the other just to prove the point; I'm not sure I have your sort of
 willpower for finishing a whole game beyond that. Though if it was a
 simple run and jump, I guess there wouldn't be that much to it?

 Surely a glut of Mario-style games is approaching! What's that? You've all
 got real jobs to do? Excuses!


 D

Fred 58: Sam Coupe book?

[Thomas Harte]

I've transcribed by hand (aside: is there an official transcription or
extraction of the various Fred articles anywhere?) Page 5 and about
two third of Page 6 of the editorial below. Did anything ever come of
the project?

The big (BIG BIG BIG) news this month is that FRED will be publishing
a book all about the SAM Coupe sometime this year. it is hoped that
the book will be out in time for Christmas this year and will include
many stories from people in the SAM world about their version of the
SAM story, and any experiences they have had. Some stories are
expected to be quite technical, while others will prove to be very
funny. At the moment, Colin is getting in touch with everyone who
could have a good story (including me...) and someone who is not
involved will decide what will make the final version.

I must stress that the book IS NOT going to be a cheap, photocopied
thing. It will be produced in the same way as any paperback novel, and
could find it's way into some computer shops around the country.

Colin Mcdonald is funding the project entirely by himself, and
although he expects to make a loss on it, feels that it is something
that many of us would like to remember our times with the SAM. at the
moment, price has not been decided.

The main reason for mentioning about this book so early is because we
are still looking for SAM stories. If you think you have a story
relating to the SAM which you think other people would be interested
in reading about, please write down your experiences and send them to
Colin. The number of contributions is likely to be very high, so
unfortunately we can't guarantee to use your article, but please don't
let this deter you from trying. We look forward to seeing what stories
you have. The deadline is the 1st September, but the earlier the
better.

(sic)

Quick attempt at a scroller

[Thomas Harte]

It's exceedingly rough and a pretty simple effect that I'm sure has
been exploited a hundred times before but I thought I'd throw it up as
is as my part in maintaining the fantastic momentum we've had lately.

http://www.clocksignal.com/dropbox/scroller.dsk

It's explicitly not a mere demo effect; adding some sprites and making
a full game is a definite possibility, though you'd probably want to
drop to 25fps — there's loads of memory free even on a 256kb machine
and it's a full, genuine Mode 4 display. The map itself is just an
array of bytes in memory, so there's no real magic there and no huge
footprint. The workflow is based on a cross-platform map editor called
Tiled so that's easy to manage.

Beyond my painful lack of artistic ability there's no reason why it
need use only one tile. Ditto for proper clipping at the edges (which,
because the tiles are precompiled, would cost more RAM but not really
any more processing).

It was full screen until the last minute, when I discovered that some
sections of the horrid little map I've hastily scribbled were a little
too slow. As you'd expect on a Sam, the trick is painting only where
you need to so level design affects speed in a less obvious manner
than being directly tied to screen area.

Re: XOR now completed!

[Thomas Harte]

I'm not sure I understand the game correctly.

• either the replay function doesn't work correctly, or it doesn't do
what I think it's meant to. Having just failed miserably to complete
the first level I let it give me a replay but if you believe that then
I never switched shield, spent a lot of time just pressing 'up' and
'down' and apparently figured out the key to view the map. Which, try
as I might, I can't. Once it was showing me the map there then
appeared to be no way out short of resetting the machine.
• completing the first level appears just to take me back to the title
screen, at which point pressing space takes me back to the first
level.

I'm forced to conclude that I'm being a dunce somehow. Any tips?

On 26 April 2012 03:14, Simon Owen simon.o...@simcoupe.org wrote:
 On 25 Apr 2012, at 21:29, Aleš Keprt wrote:

 It says: Domain http://cookingcircle.co.uk/ not found.


 It was working yesterday morning but it's now broken for me too.  I wonder
 whether it's was caught up in the UK2.net issues from yesterday, due to the
 DDOS.

 This should work in the meantime: http://cookingcircle.tumblr.com/

 Si

Re: XOR now completed!

[Thomas Harte]

I'm unable to reproduce immediately, at least on short runs; I'm not
sure if maybe my random hitting of keys (looking for that map key that
I know must be somewhere) and inconsistency of choice between QAOP and
6789 may have been a factor. On the occasion in question I'd also
played right the way out to 2000 moves.

On 28 April 2012 15:50, Balor Price toberm...@cookingcircle.co.uk wrote:
 Thanks for the feedback Thomas.

 I'm gonna take responsibility for the replay function - that sounds like my
 bug somewhere.  Something similar happened when I was playtesting but I
 couldn't replicate the error.

 The 'level' system is a bit different from most other games - because there
 are no 'lives' perse, when you finish a level it fills in a letter (or blank
 sometimes) in the level table.  Press up/down to select a different level to
 play - they can be done in any order.

 Howard



 On 28/04/2012 23:39, Thomas Harte wrote:

 I'm not sure I understand the game correctly.

 • either the replay function doesn't work correctly, or it doesn't do
 what I think it's meant to. Having just failed miserably to complete
 the first level I let it give me a replay but if you believe that then
 I never switched shield, spent a lot of time just pressing 'up' and
 'down' and apparently figured out the key to view the map. Which, try
 as I might, I can't. Once it was showing me the map there then
 appeared to be no way out short of resetting the machine.
 • completing the first level appears just to take me back to the title
 screen, at which point pressing space takes me back to the first
 level.

 I'm forced to conclude that I'm being a dunce somehow. Any tips?

 On 26 April 2012 03:14, Simon Owensimon.o...@simcoupe.org  wrote:

 On 25 Apr 2012, at 21:29, Aleš Keprt wrote:

 It says: Domain http://cookingcircle.co.uk/ not found.


 It was working yesterday morning but it's now broken for me too.  I
 wonder
 whether it's was caught up in the UK2.net issues from yesterday, due to
 the
 DDOS.

 This should work in the meantime: http://cookingcircle.tumblr.com/

 Si

Re: XOR now completed!

[Thomas Harte]

Being one of my favourite topics... the Wolfenstein algorithm is
actually incredibly inefficient. It's a linear search for every column
and then a couple of multiplies, an add and a divide to get scale.

If you instead used a combination forward/backward renderer with
portals and convex sectors, you could do significantly better for any
sort of geometry you'd expect on that level of device.

Assuming I've thought this through, costs Wolfenstein doesn't incur
would be: per visible sector you'd end up at a quadrant test, a divide
and a small table lookup per vertex, a divide, two multiplies and
three adds per visible wall. But you'd then be looking at (much the
same) two multiplies and an add every 8 or 16 columns and just two
adds per column. So you're spending a little on setup to save a lot
per column.

You'd draw front to back, zero overdraw for the world. Sprites would
be sorted per sector and I guess you'd want to walk back to the front
in sector order to paint them in, making it a stack-type thing rather
than merely a queue.

Walls could be any angle, and costs would increase as geometry
complexity increased, whereas in Wolfenstein they increase as your
rooms get larger. But freely angle walls would probably allow you to
keep the geometry simple.

Disadvantages would be indeterminate, and usually larger, level data
sizes, and the need to create a proper editor rather than just editing
in TextEdit or Notepad or whatever.

So, yes, I'm good at bluster.

On 24 April 2012 23:18,  war...@wdlee.co.uk wrote:
 Just been having a quick play!! Love that it works so fast. :-) very cool to
 see another new SAM game. How many is that now, in the last few months? Dave
 Invaders, Garden Centre of the Universe and now XOR... :-) What next??? :-D
 Those making them, should see about getting them mentioned in Retro Gamer
 magazine. They've got a section in the magazine about new games for all the
 old machines, with mini-reviews etc. Definitely worth a bit of free
 promotion and seeing your game in print on the shop shelves. :-)

 I agree with the discussion that we all concentrated on emulating the 16bit
 machines too much instead of working within the limitations to create other
 stuff, but such is the way of things. We all wanted to do what the big-boys
 could. Then again, that pushed a lot of the games further than a lot of
 people expected anyway. I suppose that's another area where the SAM was like
 the Spectrum. It wasn't technically as advanced as say the c64 in many ways,
 but competed by sheer versatility and creativity. Such was the SAM to the
 Amigas and STs. I think over the years the SAM has certainly proved it could
 do great stuff, when pushed to its limits. Who originally thought Lemmings
 would work? It's a shame we didn't see more games that weren't as limited by
 speed, like Dizzy/Flashback types.


 I'd love to see a basic test of a wolfenstein game running! :-) It'd really
 be a nice show-piece. Having said that, if someone managed to get it
 working, once the pseudo 3D engine of that was running, why not create the
 SAM's own first FPS? (Like Colin was planning with Chrome) No need to use
 the existing Wolfenstein graphics and such, when we can create our own for
 the SAM, and our own level designs, story, creatures, etc?

 Warren




 Quoting James R Curry 8...@itdoesntsuck.com:

 I remember ordering the original from one of those ZX Spectrum mail order
 places.  They were never able to deliver it, for some reason, and offered
 me the choice of another game, instead.

 No idea what I wound up buying.

 Now I can finally play it.  Looks good!  Is it in Mode 4?

 On Tue, Apr 24, 2012 at 8:21 PM, Thomas Harte
 tomh.retros...@gmail.comwrote:

 I played it for five minutes and it all looked very impressive. That
 being said, I don't actually know the original game so I was quite
 lost. Looking at the incredibly sparse World of Spectrum inlay scan
 though, I think I'm meant to work things out for myself?

 On 24 April 2012 18:00, Balor Price toberm...@cookingcircle.co.uk
 wrote:
  Hello everybody
 
  I'm proud to present my conversion of the 1987 Spectrum game XOR.  I
 finally
  kept my promise to my teenage self to finish a SAM game!
 
  You can download it for free from the revived
  http://cookingcircle.co.uk
 
  I hope you enjoy it (and yell in frustration).  It's 25 years old and
 still
  as rock-hard as I remember.
 
  Any feedback/initial bugs found would be greatly appreciated.  :D
 
  Cheers
  Howard




 --
 James R Curry
 8...@itdoesntsuck.com

Re: Nyan Cat

[Thomas Harte]

I had a brief look at it; given that the originals are 400x400 (and,
as you noted, not actually simply an upscaling of a smaller size,
despite consciously adopting that look), I assume you repainted by
hand?

On 24 April 2012 11:13, Aleš Keprt a...@keprt.cz wrote:
 My conversion of original graphics is already finished, so I look forward to
 your music. :-)
 I wanted to ask for help the people who did music for some other 8bit
 conversion(s).
 Aley

 From: David Sanders
 Sent: Tuesday, April 24, 2012 10:59 AM
 To: sam-users@nvg.ntnu.no
 Subject: Re: Nyan Cat


 On 23 April 2012 21:34, Thomas Harte tomh.retros...@gmail.com wrote:

 If it's for some sort of quick attempt at multipart megademo (albeit
 with all the parts being extremely similar), would it be safe to
 assume that someone [else] is working on the music? I'd love to be
 able to contribute but music is completely beyond me.


 I'm loathe to put myself forward for this, but what the hell. I'll convert
 the music :-)

 -
 Mgr. Aleš Keprt, Ph.D.
 private: a...@keprt.cz, www.keprt.cz
 office: Moravian College / Moravská vysoká škola Olomouc, ales.ke...@mvso.cz

Re: Nyan Cat

[Thomas Harte]

I guess it was easy to put in something like an optional shift right
by three to compose scan line number and column number when fetching
attributes, hence to allow Mode 1 and 2, but would have been harder to
have alternative attribute interpretation logic? I'm unsure why they
decided to go bright + flash in the Spectrum, to be honest. Was
flashing a must have feature of the 1982 computer market?

I think I'm right to say the American Timex machines have the
equivalent of Mode 2?

A pretend 64x96 mode could allow for some neat effects. I'll wager you
could do Wolfenstein in it, based on the CPC seemingly being to cope
in its 64-bytes-for-128-pixels mode, per YouTube. Following that line
of logic through, anything on the CPC that isn't using a hardware
scroll should be an option.

2012/4/24 James R Curry 8...@itdoesntsuck.com:
 The strangest decision regarding Mode 2 is keeping the BRIGHT and FLASH
 attributes.  Without those, the Ink and Paper colours could each be any of
 the sixteen colours.  As it is, the select colours have to both be in the
 range 0-7 or 8-15, not one in each range.

 Incidentally, has anyone thought about clever use of Mode 2 and attributes
 to create a game that runs at a super low resolution, like 64 x 96 (using
 4x2 pixel blocks)?

 It could run at a high frame rate...  it might be an interesting experiment

Re: Nyan Cat

[Thomas Harte]

Agreed on James' comments re:Wolfenstein; from here in 2012, I'm much
more able to suspend by disbelief for Elite, though I think
Wolfenstein's problems go far beyond merely the style of graphics.

I'd also forgotten the Manic Miner loading screen! Thank goodness for
the flash attribute!

On 24 April 2012 16:41, Ian Collier ian.coll...@cs.ox.ac.uk wrote:
 On Tue, Apr 24, 2012 at 04:16:28PM -0700, Thomas Harte wrote:
                                                  I'm unsure why they
 decided to go bright + flash in the Spectrum, to be honest. Was
 flashing a must have feature of the 1982 computer market?

 No but you forget one thing... the cursor. :-)

 imc

Re: Nyan Cat

[Thomas Harte]

Per The Register's extended article celebrating the Spectrum's
birthday yesterday, there was more than a kilobyte of spare space in
the ROM but they intended to put the Microdrive stuff in there before
shipping. In the event it wasn't ready in time and the machine sold
too well for the intended free ROM upgrade to make economic sense.

So, with hindsight:
• no flash attribute (ideally starting on the Spectrum, but at least in Mode 2);
• a graphics mode that uses the Mode 2 amount of data for 128
non-attributed pixels per line;
• hardware scrolling.

Hooray for hindsight!

On 24 April 2012 16:45, James R Curry 8...@itdoesntsuck.com wrote:
 Given that, at least going from my memory, there was space to spare in the
 original ZX Spectrum ROM, the flashing cursor in Spectrum BASIC could have
 quite easily been implemented with interrupts and each character square
 could have had complete freedom to pick any two of sixteen colours.

 But what do they say about hindsight?


 On Tue, Apr 24, 2012 at 6:41 PM, Ian Collier ian.coll...@cs.ox.ac.uk
 wrote:

 On Tue, Apr 24, 2012 at 04:16:28PM -0700, Thomas Harte wrote:
                                                   I'm unsure why they
  decided to go bright + flash in the Spectrum, to be honest. Was
  flashing a must have feature of the 1982 computer market?

 No but you forget one thing... the cursor. :-)

 imc




 --
 James R Curry
 8...@itdoesntsuck.com

Re: XOR now completed!

[Thomas Harte]

I played it for five minutes and it all looked very impressive. That
being said, I don't actually know the original game so I was quite
lost. Looking at the incredibly sparse World of Spectrum inlay scan
though, I think I'm meant to work things out for myself?

On 24 April 2012 18:00, Balor Price toberm...@cookingcircle.co.uk wrote:
 Hello everybody

 I'm proud to present my conversion of the 1987 Spectrum game XOR.  I finally
 kept my promise to my teenage self to finish a SAM game!

 You can download it for free from the revived http://cookingcircle.co.uk

 I hope you enjoy it (and yell in frustration).  It's 25 years old and still
 as rock-hard as I remember.

 Any feedback/initial bugs found would be greatly appreciated.  :D

 Cheers
 Howard

Re: Nyan Cat

[Thomas Harte]

If it's for some sort of quick attempt at multipart megademo (albeit
with all the parts being extremely similar), would it be safe to
assume that someone [else] is working on the music? I'd love to be
able to contribute but music is completely beyond me.

Re: Aley's comments on a 4bpp 64-byte pitch mode (so, the same number
of fetches as Mode 2, even with the same memory layout if they really
wanted, but to produce a 128x192 display), I'd have been all for it,
even as a replacement for Mode 2. Though obviously hardware scrolling
would be quite a way above it on a wish list...

On 23 April 2012 13:24,  da...@properbastard.co.uk wrote:
 Quoting Balor Price toberm...@cookingcircle.co.uk:

 Hang on, am I really doing this??!!  (reality kicks in) Hell no!!  Not
 until I finish some /real/ stuff anyway

 Howard


 Do a send-up using the SAM Robot instead! :)

Re: Musics

[Thomas Harte]

The best idea I've come up with is to use a very limited number of tiles
and scroll like one of those infinite ball demos.

So, you have 8x8 tiles and 8 screen buffers. You scroll only either 1 or
zero pixels at a time, only ever in one direction. Assuming it's a right to
left scroll, for each movement you switch from one buffer to the next. Then
run through each on-screen tile and paint only if that tile is not the same
as the tile one position to its left.

With a small number of possible tiles and a normal sort of platform game
layout (ie, lots of horizontal platforms) you shouldn't have to draw all
that much. Level two of Super Mario Brothers would probably be an ideal
usage case.

I guess that the next thing would be to store your tile map as the computed
list of tile changes to draw per tile column, and to consider whether
compiling your tiles so that you map from the combination of old tile and
new to the code and draw only the changes gives a meaningful boost for the
memory cost.

I'm not sure whether anybody else has done this sort of thing, but I really
mean to give it a go sometime soon.

On Saturday, 21 April 2012, Adrian Brown wrote:

 That’s top, im a child of the electronic sound – don’t think my wife is
 too impressed with it blasting out of the office though ;)  Im working on
 some other sam bits at the moment (when time allows)  For programmery
 people, scrolling on sam is what let it down imho.  Thinking of something
 like sanxion, who has some ideas on how to move that much data.  Im
 guessing it would have to be mode 2 to really be able to get a decent speed
 scroller.  Ive tried various things for a decent speed scroll mode 4, but
 it just doesn’t seem possible if you want a lot of graphics on screen, even
 with compiled block data.

 ** **

 Adrian

 ** **

 *From:* owner-sam-us...@nvg.ntnu.no javascript:_e({}, 'cvml',
 'owner-sam-us...@nvg.ntnu.no'); 
 [mailto:owner-sam-us...@nvg.ntnu.nojavascript:_e({}, 'cvml', 
 'owner-sam-us...@nvg.ntnu.no');]
 *On Behalf Of *David Sanders
 *Sent:* 20 April 2012 11:16
 *To:* sam-users@nvg.ntnu.no javascript:_e({}, 'cvml',
 'sam-users@nvg.ntnu.no');
 *Subject:* Musics

 ** **

 Hello List,

 ** **

 If anyone fancies a listen to the most fiendishly complicated piece of Sam
 music I've written, here it is:

 ** **

 http://dsanders.co.uk/sanxion.dsk

 ** **

 It's kind of a conversion of Rub Hubbard's Sanxion loader, but done from
 memory so probably quite different. I believe the effect at around 2:00 has
 never been done before on the Coupé! A first time for everything even on
 the Sam eh? So, why did I spend my morning writing this? Your guess is as
 good as mine, but I reckon someone now ought to make the effort to convert
 the actual game. Ahem.

 ** **

 Cheers

 ** **

 ** **

 David

 ** **

Re: Musics

[Thomas Harte]

If I dare jump in, I'd phrase it the other way around. The source media is
the authoritative copy; hacks and cracks are the compromises.

On 20 April 2012 13:48, Aleš Keprt a...@keprt.cz wrote:

   Yes, but these compromises are needed for 1 disk of 100, while 99 of
 100 do work with DSK. So if somebody sends us his new ETracker tune in EDSK
 format I ask myself: Is this really what we needed?

 Btw. I haven't seen SAMdisk utility before. It looks nice. I slept many
 years or something. [image: Mrkající veselý oblicej] Please can you tell
 me the format of TRD (Beta128 TRDOS images)? Is it the same as DSK? Or is
 it like SAD without header? I read the documentation you link from your
 website, so I know the internal data format, but I can't see the actual TRD
 file format described there. Thanks in advance.

 Aley

   *From:* Simon Owen simon.o...@simcoupe.org
 *Sent:* Friday, April 20, 2012 10:40 PM
 *To:* sam-users@nvg.ntnu.no
 *Subject:* Re: Musics

 Aley,

 I'd started to type a longer reply to this, but I just can't be bothered
 anymore.  It's clear we have very different approaches to pretty much
 everything.  I'm just not willing to make the same compromises as you when
 it comes to preserving media.  If it doesn't work without modifying it, you
 need a better quality copy.

 Si


  On 20 Apr 2012, at 20:07, Aleš Keprt wrote:

   You know my disk extractor and other utilitie are dated 199x.

 And I don't like this. I think 95% or even more of disks overall don't
 need any special disk formats, and there are many software utilities which
 support simple DSK/MGT/SAD because those programs are much older than 2005.
 It isn't a clever idea to design a whole new file format 15 years after Sam
 Coupe was born and use it for all disks even when it is not needed for most
 of them. Also those two SDF files can be downloaded from some websites, but
 I haven't seen any protected EDSK files anywhere, so I would prefer
 sticking with the same formats. Don't change what works. Also this is the
 first time I have seen EDSK file on my own eyes, and I wonder why it has
 DSK extension when it is not a real old good DSK file. I looked at the file
 in heax view and I can see Amstrad CPC header in it. Note that I created my
 SAD format only because it was years before DSK format was known to me, and
 also I have several 840KB disks which are a bit problematic in DSK
 especially in some software which automatically expect 800KB DSK only. But
 otherwise DSK is enough for most of disks.

 I think it would be OK if we had this file format around 1995 when there
 was a real big need to backup our disks, but not in 2005 when 99% of disks
 are converted and possibly cracked to be converted without any special file
 formats.

 Aley

  *From:* Simon Owen simon.o...@simcoupe.org
 *Sent:* Friday, April 20, 2012 7:36 PM
 *To:* sam-users@nvg.ntnu.no
 *Subject:* Re: Musics

  On 20 Apr 2012, at 17:25, Aleš Keprt wrote:

   I'd like to know why do you use Amstrad CPC file format, instead of a
 standard Sam Coupe one (DSK/MGT or SAD).


 EDSK has been an adopted format in the SAM scene at least as far back as
 2005.  It's the only way to preserve some disks in their original format,
 allowing for unformatted tracks, disk errors and other custom-formatting
 tricks.  EDSK seemed like a reasonable solution at the time, without
 inventing yet another disk image file format.

 Before that was finalised I did still create SDF as a temporary solution.
 Only two public disk images ever existed (Lemmings and Prince of Persia),
 and I don't think the creation tool was every released.  All support for
 SDF was dropped from SimCoupe a few months back, so it's effectively dead

Re: Musics

[Thomas Harte]

Attempting to vote takes me through to a blank page -- is that what you saw?

On 20 April 2012 18:16, James R Curry 8...@itdoesntsuck.com wrote:
 It's a Wiki about the Sam world but has some disk images hosted which I 
 believe you can access from their product pages.  It also has broken polls.  
 At least it did today when I tried to vote on one.

 --
 James R Curry


 On Apr 20, 2012, at 8:13 PM, Aleš Keprt a...@keprt.cz wrote:

 Really? I didn't know it. Believe me, I don't lie, I never saw any EDSK or
 at least I don't remember any.
 I don't know much about World of Sam. It is something like NVG FTP archive?
 Aley

 -Původní zpráva-
 From: Andrew Collier
 Sent: Saturday, April 21, 2012 2:59 AM
 To: sam-users@nvg.ntnu.no
 Subject: Re: Musics


 On 20 Apr 2012, at 20:07, Aleš Keprt wrote:

 I haven't seen any protected EDSK files anywhere,

 Almost all the previously-commercial software on worldofsam.org, for a
 start.

 Andrew


 -
 Mgr. Aleš Keprt, Ph.D.
 private: a...@keprt.cz, www.keprt.cz
 office: Moravian College / Moravská vysoká škola Olomouc, ales.ke...@mvso.cz

Re: ZX Spectrum 'relaunch'

[Thomas Harte]

For the purposes of debate, I think the counterargument would be that
a software approach is inherently more portable and so more
maintainable and more suited to a wide audience. Furthermore, there's
no automatic advantage to doing things in hardware, given that these
systems are fully deterministic and well understood, other than that
it can be easier to get right, but that's primarily because the
emulation mindset doesn't normally consider absolute accuracy to be a
paramount concern. That's why you very often see people write
emulators where interrupt timing is rounded to the nearest whole
instruction, palette changes are accurate only to the nearest whole
scan line, etc. Authors often prefer to make a subjective judgment
about what's 'accurate enough' so that they can prioritise ease of
development and/or performance.

Summary then: emulation carries no inherent accuracy penalty.

Alternatively, as a person who prefers functionality, surely you can
see the benefit in emulation, which is all functionality and no form?
The hardware becomes a completely orthogonal issue.

On 13 April 2012 11:32, Aleš Keprt a...@keprt.cz wrote:
 I don't share your thoughts. There already exist a lot of Spectrum clones
 based on real ULAs and real Z80 and imo these are much better alternatives
 than what you described. You can already buy anything you can imagine. So
 many alternatives already exist and were created by huge fan base in the
 past, that I can hardly imagine that somebody can really come today driven
 by just marketing or business visions and create something significantly
 better or more compatible or more useful.

 For example: I personally prefer functionality, not the look of that crappy
 original keyboard. So I would prefer a PC keyboard, CF memory card instead
 of tapes or disks, and real ULA (i.e. 100% accurate ULA clone), standard 128
 KB RAM, and real Z80 CPU.
 For other people who prefer or require the original ZX Spectrum case, they
 can buy a new internals - this was already possible to buy 10 or more
 years ago. (I personally has a working original ZX Spectrum+ and working
 original Sam Coupe. :-))

 I think you are too focused on emulators - why would anybody put a today's
 computer with an emulator inside an old ZXS box? It's just funny, not
 worthy. I prefer either emulator on a proper PC computer, or original 8bit
 Zilog Z80 in an original box. :-))

 Aley

 -Původní zpráva- From: war...@wdlee.co.uk
 Sent: Friday, April 13, 2012 12:18 PM

 To: sam-users@nvg.ntnu.no
 Subject: ZX Spectrum 'relaunch'

 Off on a bit of a non-SAM tangent (but probably somewhat related for
 most of us) I came across this the other day:

 http://www.telegraph.co.uk/technology/video-games/8304237/ZX-Spectrum-relaunch-gaming-goes-back-to-the-future.html

 Lots of you have probably already heard this, but I don't remember it
 being mentioned, so thought I would! ;-)

 Supposedly a company were going to relaunch the zx spectrum this year
 (by the looks of it, as a 48k speccy keyboard that links up to an
 iPhone or similar to run an emulator), to coincide with the 30th
 anniversary, but it doesn't look like it's going to materialise any
 time soon. I know something similar is/was being planned for the C64?

 However, it got me thinking... Obviously in this day and age, many of
 use want to enjoy the retro gaming experience, but we haven't exactly
 got the space to keep things set up. I intend to have my SAM set up
 permanently at some point, but I very much doubt I'd ever get the
 space to dedicate to other systems, so clearly something that
 pleasantly replicates the original experience quickly and easily with
 modern advantages would be a pleasing alternative.

 So I figured, what would make an easy to use 'spectrum' emulator for
 playing all the old games? You'd want HDMI output for ease with modern
 televisions, SD card storage, and have it all fit into one of our old
 rubber keyed friends. How do you do this on a budget at that size? The
 first thing that popped into my head, is the Raspberry Pi (if it ever
 gets to selling!!). Small enough to probably fit in a speccy case,
 with HDMI out and card reader. Surely this could make for a fairly
 cheap and effective 48k Spectrum emulation experience?

 I think the Speccy is particularly suited, because let's face it, for
 most of us it was about the games more than anything. I don't think
 anything similar would work for the SAM, because what makes that such
 a unique experience (for me, anyway) is the original and additional
 hardware in addition to the software. But for a speccy I could see it
 being great fun, to play the games with ease on a keyboard that
 replicates the old experience but with updated advantages. (I think a
 SAM equivalent would have to be more along the lines of Colin's
 'SAM-in-a-can' projects, but rather than old SAM parts, something that
 accurately replicates the original hardware with modern additions)

 Not being much of a tech person 

Re: Weird caps lock behaviour

[Thomas Harte]

I'm not a Windows user so am unable directly to comment, but is SDL or
some other cross-platform library possibly contributing to the
confusion?

Here in Mac world the caps lock key is a special case. It sends a key
down when caps lock is engaged and a key up when caps lock is
disengaged. That was originally because original Mac keyboards had a
caps lock key with a little latch, like a pen with a button, so that
you pressed it once and it stayed down, you pressed it again and it
popped back up, and I guess it continues because Apple don't consider
it sufficiently worrisome to be worth the mild breakage.

Slightly boring history lesson of a minority platform aside, when last
I checked SDL handled this problem by emulating Mac behaviour on all
platforms. It looks like in ye olde ASCD you used Allegro. I doubt
those guys had any particular strategy for handling this, and even if
they did they probably got it wrong, then squabbled over maintaining
DOS support ten years after the fact.

So, anyway: is there any possibility that either you and other authors
are seeing differing results because some are using cross-platform
libraries that attempt to reconcile Mac and PC behaviour?

On 8 April 2012 12:43, Aleš Keprt a...@keprt.cz wrote:
 Hi Sam users!

 I encountered a weird caps lock behaviour, and I'd like you to test it too
 and let me know whether you encounter the same problems or not. On my
 computer all emulators I tested have got problem with caps lock - it simply
 doesn't work as expected. So I made changes to keyboard handling routine in
 ASCD 0.98 to let it work. And now this new version is the only emulator
 where caps lock works correctly on my computer, but Simon Owen wrote me that
 on his computer it is different and ASCD 0.98 doesn't work correctly like
 other emulators.

 Please can you test it? If you compare ASCD 0.98 with SimCoupe, you should
 clearly see difference in caps lock behaviour in Sam Basic. You can also
 test older ASCD 0.98 WIP which uses the old (i.e. standard) caps lock
 routine and will probably be similar to SimCoupe.

 Download here:
 http://www.keprt.cz/progs/ascd/ascd098.zip
 http://www.keprt.cz/progs/ascd/ascd098wip3.zip

 ---

 Technical information follows:

 Normally each key sends KEYDOWN when you press it, then it waits 250 ms
 (this can be set in Windows) and then sends another KEYDOWN's as long as you
 hold down the key. The speed of autorepeat can be set in Windows as well,
 normally it sends 30 KEYDOWN's per second on my computer (which is the
 highest speed possible on a standard PC keyboard). Finally it always sends a
 single KEYUP when you release the key.

 Caps lock sends initial KEYDOWN normally, then waits 250 ms (i.e. still
 everything normal), but when you hold down the key longer, it starts to send
 weirdly KEYUP - KEYDOWN - KEYUP - KEYDOWN... etc. at 30 events per second
 (i.e. 15x KEYUP and 15x KEYDOWN). When you release the key, the final event
 sent is based on the state of the green caps lock led on the keyboard. So
 you
 can never know if the final event will be KEYDOWN or KEYUP.

 I use Windows 7 with plain standard PS2 keyboard driver, at least I think. I
 will definitely go and test it on other computers (I have a few old ones at
 home).

 -
 Mgr. Aleš Keprt, Ph.D.
 private: a...@keprt.cz, www.keprt.cz
 office: Moravian College / Moravská vysoká škola Olomouc, ales.ke...@mvso.cz

Re: Junk mail

[Thomas Harte]

Well that's an email I hadn't spotted. And there's a difference
between being a troll and reacting badly in an argument but I
certainly wouldn't want to be Roger's defence counsel.

On 6 April 2012 14:00, Wayne Weedon wa...@fdos-design.com wrote:
 On 06/04/2012 21:16, Tommo H wrote:

 I received five emails this morning, at least two of them to the same
 long list of people as those that started this conversation.

 For the record, I've never considered him to be a troll because he
 doesn't seem deliberately to be trying to annoy anyone, and his
 messages aren't deliberately provocative so much as just a little
 confusing.


 He seemed to had gone off on one!

 http://blog.gmane.org/gmane.comp.systems.sam-coupe

 fascists??

Re: SAM HAM viewer

[Thomas Harte]

An additional observation: this might finally be an application for
the Kaleidoscope?

On 5 April 2012 17:10, Simon Cooke si...@popcornfilms.com wrote:
 I thought about doing something like this a while back, but as ever didn't
 get chance to play with the idea. For me, the trick would have been to say
 screw it and randomly/genetically generate the code required to change the
 palette. On modern CPUs it shouldn't take more than a few hours to
 generate/simulate even if you're brute forcing it.

 Now, of course, once you get to dithering the image and optimizing that,
 you're starting to explode the solution space but it's not exactly
 insurmountable.

 (I've got a 2 year old daughter and enough work to sink a battleship these
 days, so unfortunately as much as I hate to say it, I think my SAM
 programming days are done :'( ).
 
 From: Simon Owen
 Sent: 4/3/2012 2:43

 To: sam-users@nvg.ntnu.no
 Subject: Re: SAM HAM viewer

 On 2 Apr 2012, at 23:58, Thomas Harte wrote:
 I think that used a tight loop of something like (i) load next palette
 index,
 next colour and next delay length; (ii) push colour to palette index;
 (iii) perform a busy loop of the desired length; (iv) repeat.

 That's closer the approach I was originally aiming for, but the conversion
 is far more complicated.  For a first attempt I restricted it to changing
 the CLUT when the raster was outside the image, which still gives a
 noticeable improvement over a static palette.

 My ideal approach would even eliminate steps (i) and (iii), and just use a
 huge unrolled loop of OUTI instructions.  That would update 1 CLUT entry per
 instruction in reverse order, in a continuous loop.  The converter would be
 tracking a rolling window colours, with knowledge of colours no longer
 needed and look-ahead to what can be set up in advance.  It also needs to
 understand the instruction timing, which varies across the scanline.
 Thinking of implementing that still makes my head hurt!


 but you could instead, say, change a single palette index several
 times over the course of a single scan line, or anything in between.

 I considered individual CLUT updates for my current viewer, but it took too
 much time away from the actual updating — the extra LD B,n needed costs
 about the same has half an OUTI.  Instead I grouped the dynamic colours
 together and updated them with a small unrolled OUTI block.


 If you have portions of the image with only four colours (especially
 once the colour aliasing forced by the 128-colour palette is accounted
 for) then switching to mode 3 for a portion of a line could be the smarter
 thing to do, and would presumably cost basically nothing to implement?

 Unless you need the extra resolution, I don't think there's anything to gain
 from using mode 3.  It uses a subset of the mode 4 CLUT, so it doesn't help
 with fast access to an alternative colour set.  Or am I missing something?

 Si

Re: Junk mail

[Thomas Harte]

He did the skull animation that Aleš posted about just recently,
didn't he? Which is a tape file of a 25 fps animation that a suitably
accelerated emulator — such as ASCD — can play as a video.

On 5 April 2012 11:52, James R Curry 8...@itdoesntsuck.com wrote:
 Or the 14 disk collection of screen captures he'd release...

 --
 James R Curry


 On Apr 5, 2012, at 1:48 PM, Chris Pile chris.p...@blueyonder.co.uk wrote:

 The geezer's a prize numpty!  I just got hit with 30-odd Onspeed Software 
 Recommendation
 emails and a whopping 8.29 MB email - the contents of which is anyone's 
 guess!  Although I
 imagine it's dozens of screen captures, as that seems a favourite of his.  
 Suffice to say I didn't
 bother opening any of them - select-all/delete...  Job done!

 Why doesn't he channel the energy he puts into spamming into doing something 
 constructive
 on the SAM?  Bloody hell, imagine the mega-game or ultra-utility that would 
 arrive if he did!





 - Original Message - From: Wayne Weedon wa...@fdos-design.com
 To: sam-users@nvg.ntnu.no
 Sent: Thursday, April 05, 2012 7:13 PM
 Subject: Re: Junk mail
 Well seems a lot of us have blocked his madness now.  Hopefully he'll get 
 pissed off with not getting any attention if hardly anyone see's the crap.
 It used to be facebook and Linkedin requests only.   Got caught with his 
 pants down this time with the harvesting attempt we saw in the list!
 Wayne...

Re: SAM HAM viewer

[Thomas Harte]

I've seen something similar on the Atari Lynx, which also has a 4 bit
frame buffer, the only difference being that I think that used a tight
loop of something like (i) load next palette index, next colour and
next delay length; (ii) push colour to palette index; (iii) perform a
busy loop of the desired length; (iv) repeat. The loop was
synchronised once with vertical retrace and timings were such that a
degenerate case was to change the entire palette once after every scan
line but you could instead, say, change a single palette index several
times over the course of a single scan line, or anything in between.

A better adaption for the Sam might be to allow palette and mode
changes, and for simplicity to add a delay length that just means to
wait until the next vertical retrace? If you have portions of the
image with only four colours (especially once the colour aliasing
forced by the 128-colour palette is accounted for) then switching to
mode 3 for a portion of a line could be the smarter thing to do, and
would presumably cost basically nothing to implement?

In terms of image conversion, I guess a heuristic would be the thing.
It feels like, even at Sam size, an exhaustive search could take
forever.

Of course, I didn't disassemble Simon's fantastic work so it's
possible he's way ahead of me on this one.

On 1 April 2012 18:05, Aleš Keprt a...@keprt.cz wrote:
 Oh yes, this is nice. I saw similar things in the past, AFAIR this was
 published on some disk magazine back in 90's. But it will be hard to find it
 now.

 So how many colours are possible per line in this format? Or what is
 possible in this picture format?

 Also, I think that the converter could possibly de-noise the picture before
 or after the conversion. Or something like that. Because there are too many
 dots visible in places where there should be no dots. This is good in high
 resolution graphics like when printing on printer in 600 DPI, but doesn't
 look too well on Sam. Especially in emulator with crisp LCD display. ;-) I
 think the whole de-noising process is extremely important when converting to
 low resolution and low bitdepth. And each single picture needs a different
 values for the algorithm, so maybe there should be some kind of WYSIWYG
 editor or something where users could change some settings and see the
 result immediately in order to find the best settings for each file. ;-)
 Maybe a genetic algorithm could help to find at least some local optimum.

 /---
 Aley

 -Původní zpráva- From: Simon Owen
 Sent: Saturday, March 24, 2012 3:10 AM
 To: sam-users
 Subject: SAM HAM viewer


 Hi all,

 I've been experimenting with HAM-style tricks on SAM, to try to improve
 the quality of converted images.  I've aimed to modify as many colours
 as possible between lines, rather than using the traditional compromise
 static palette.  Are there any viewers using that technique already?

 I've written a Python script to convert regular images to a new .sham
 format, and a SAM viewer program to display them.

 Demo: http://simonowen.com/sam/shamview/shamview.dsk
 Source code: https://github.com/simonowen/shamview

 You might recognise some of them as SAM or image processing favourites!

 It still needs work on the dynamic palette selection, which just uses
 the most-frequent colours, rather than doing proper quantisation.  I
 left the crayons image as an example of this breaking down.

 Si

 -
 Mgr. Aleš Keprt, Ph.D.
 private: a...@keprt.cz, www.keprt.cz
 office: Moravian College / Moravská vysoká škola Olomouc, ales.ke...@mvso.cz

Re: Dave Infuriators

[Thomas Harte]

Even better — put it in a public repository and hope that somebody
else cleans it up!

In reality, if it fits the pattern of just about everything I've ever
published then very few people will ever look at it, so what you're
mainly getting is a free backup, a free inter-machine synchronisation
tool and an excuse to hold yourself to a higher standard. The odd
email every few years when someone stumbles upon your stuff and wants
to discuss it is a bonus.

On 15 March 2012 02:32, Adrian Brown adr...@apbcomputerservices.co.uk wrote:
 I can look at something like that, trouble is at the moment its just 
 collections of random source files ;)

 -Original Message-
 From: owner-sam-us...@nvg.ntnu.no [mailto:owner-sam-us...@nvg.ntnu.no] On 
 Behalf Of Thomas Harte
 Sent: 15 March 2012 02:30
 To: sam-users@nvg.ntnu.no
 Subject: Re: Dave Infuriators

 Any chance of joining the GitHub gang (or any other online repository) if 
 you've got code you're generally sharing?

 I've finally been motivated to start commenting my 3d stuff properly.
 Andrew's great work sort of makes me want to try to break out of my comfort 
 zone and try some 2d and I'm definitely excited about Dave Infuriators. I 
 hate to attach the word to it because of the Sam's legacy, but I really like 
 puzzle games.

 On 14 March 2012 13:11, Adrian Brown adr...@apbcomputerservices.co.uk wrote:
 Give me a shout if you want to save from assembler. Ive got various
 code that can do that using DOS hooks (no custom code as that's a pain
 with SD cards etc)

 Adrian

 -Original Message-
 From: owner-sam-us...@nvg.ntnu.no [mailto:owner-sam-us...@nvg.ntnu.no]
 On Behalf Of Andrew Gillen
 Sent: 13 March 2012 23:31
 To: sam-users@nvg.ntnu.no
 Subject: Re: Dave Infuriators

 Pleased you're all looking forward to it :)

 I'm looking to include the level editor as part of the release, though
 I need to figure out how to save data to disk. It's all well and good
 loading using the SAM DOS hook codes but saving I'm not so sure about.

 I have yet to tackle this, but does anyone have any tips?

 It was a miracle I managed to get this and Dave Invaders loading stuff
 during runtime ! I suppose I could drop back out to basic and have the
 basic listing deal with saving the block of level data out on exit
 from the editor maybe, but that seems a bit ham-fisted for want of a
 better term.

 --
 From: the wub the...@gmail.com
 Sent: Thursday, March 08, 2012 8:29 PM
 To: sam-users@nvg.ntnu.no
 Subject: Re: Dave Infuriators

 This looks like great fun!  The background graphics are really
 effective too, can't wait to have a go! :)

 Rob.

Re: Dave Infuriators

[Thomas Harte]

Any chance of joining the GitHub gang (or any other online repository)
if you've got code you're generally sharing?

I've finally been motivated to start commenting my 3d stuff properly.
Andrew's great work sort of makes me want to try to break out of my
comfort zone and try some 2d and I'm definitely excited about Dave
Infuriators. I hate to attach the word to it because of the Sam's
legacy, but I really like puzzle games.

On 14 March 2012 13:11, Adrian Brown adr...@apbcomputerservices.co.uk wrote:
 Give me a shout if you want to save from assembler. Ive got various code
 that can do that using DOS hooks (no custom code as that's a pain with
 SD cards etc)

 Adrian

 -Original Message-
 From: owner-sam-us...@nvg.ntnu.no [mailto:owner-sam-us...@nvg.ntnu.no]
 On Behalf Of Andrew Gillen
 Sent: 13 March 2012 23:31
 To: sam-users@nvg.ntnu.no
 Subject: Re: Dave Infuriators

 Pleased you're all looking forward to it :)

 I'm looking to include the level editor as part of the release, though I
 need to figure out how to save data to disk. It's all well and good
 loading using the SAM DOS hook codes but saving I'm not so sure about.

 I have yet to tackle this, but does anyone have any tips?

 It was a miracle I managed to get this and Dave Invaders loading stuff
 during runtime ! I suppose I could drop back out to basic and have the
 basic listing deal with saving the block of level data out on exit from
 the editor maybe, but that seems a bit ham-fisted for want of a better
 term.

 --
 From: the wub the...@gmail.com
 Sent: Thursday, March 08, 2012 8:29 PM
 To: sam-users@nvg.ntnu.no
 Subject: Re: Dave Infuriators

 This looks like great fun!  The background graphics are really
 effective too, can't wait to have a go! :)

 Rob.

Re: ASCD 0.98 WIP 1 - new version of the emulator available

[Thomas Harte]

I don't use Windows so was mainly going along to see if you still
release source, but from here the only entry your page shows for ASCD
is ASCD 0.96 [11.09.2002] (binary: 311KB, source: 128KB). So I'm not
sure if there's a caching issue or something else at play?

Also, since the Spectrum is an average of about 1500 baud (zeros and
ones being different lengths, of course) I guess 33 mb would take up,
ummm, about 50 hours of tape? That's 35 C90s.

On 12 March 2012 18:21, Aleš Keprt a...@keprt.cz wrote:
 Hi Sam Coupe fans,

 I just uploaded the new version of my Sam Coupe emulator ASCD to my website.
 It’s 10 years since last public release. :-D

 It is “work in progress” release. It emulates ZX Spectrum 48, 128, and Sam
 Coupé. There are two or three reasons why I resurrected this old project:

 1. It was originally meant to be “Aley’s SimCoupe for DOS” aka ASCD. But
 MS-DOS is dead, so I converted whole project to Windows. I did this Windows
 port back in 2003 and we used it as a ZXS emulator in game tournaments. But
 there were strange bugs in Sam emulation I wasn’t able to find, so I never
 released that version 0.97 to public. Now I finally found that strange main
 9 old bug. :-)

 2. I plan to add support for Sam Coupe snapshots, QuickSave/QuickLoad
 together with action replay recording. The today’s version already contains
 support for QuickLoad/QuickSave, so you can play the games more easily. ;-)
 But all saved ”quick” snapshots are discarded when you restart the emulator.
 I need first to discuss the snapshot file format with Simon Owen to make it
 usable in SimCoupe too, then I will publish the final version.

 3. Finally, I want to add support for video recording with
 QuickSave/QuickLoad. I hope some game players will record game progress of
 some games to a video file. Of course it is a bit unfair to use
 QuickSave/QuickLoad when making video recording, but it can help us to
 compose a really “best” plays. I look forward to it. :-)

 If you are interested, download the emulator from my Downloads page:
 http://www.keprt.cz/progs/
 Please let me know whether it works correctly on your computer or not.
 Required configuration is simple: Windows 2000 or later, DirectX 6 or
 Direct3D 9

 ---

 I also recommend you to try this:
 http://www.keprt.cz/zx_girlsaloud_something_kinda_ooh.tap.gz
 It is a video file in TAP (ZX Spectrum tape file) made by Roger Jowett.
 Warning: It is 33 MB long, 11 MB compressed.
 You can load it in ZX Spectrum mode (use menu to insert the tape, then
 switch to ZXS 128 and press Enter). I wonder how many real tape casettes
 would it take to save those 33 MB of data. :-D
 ASCD emulator supports TAP tapes in Sam Coupe mode too. Maybe somebody will
 create similar crazy videos for Sam Coupe. The size of tapes is virtually
 unlimited, so it is possible to create almost anything when you use
 infinite-load speed of the emulator.

 Best regards,
 Aley Keprt

Re: Emulation etc...

[Thomas Harte]

Per 
http://www.raspberrypi.org/forum/general-discussion/some-very-good-audio-news
:

... you will be able to deal with two high-quality audio streams, one
via HDMI and one through that jack

So it's implied there's a completely separate audio route that goes to
the 3.5mm jack output, unrelated to the HDMI. My guess would be that
you can't get audio out through HDMI other than through the
(proprietary, closed) video decoder but you'll be able to use the jack
for whatever you want.

On 18 February 2012 10:23, Simon Owen simon.o...@simcoupe.org wrote:
 Previously I wrote:
 It should still be possible to add a USB sound device, at the cost of
 one USB port.  Hopefully not too much extra latency either.

 I've just tested this out with my HP Microserver Linux box, which also
 lacks sound hardware.  I had a USB sound device that came with my
 Sennheiser headset, which I don't normally use with my PC.

 I just plugged the USB widget in, fired up SimCoupe over a remote X
 session and it ran fine with sound (new sound-sync code too).  No
 noticeable difference in latency either.


 On 17/02/2012 20:27, da...@properbastard.co.uk wrote:
 Perhaps it's possible to emulate a simulated accelerated SAM then :)

 There will be choice of running speed, though it'll still be 6MHz from
 SAM's point of view.  True acceleration would break any time-critical
 effects, and ASIC contention would eat much of the extra speed anyway.

 Si

Re: GitHub and a polygon filling routine

[Thomas Harte]

 Mine was mostly being lazy, so I don't have to managing separate source
 archives for each binary release.

Having thought about it, and especially comparing my stuff to yours, I
think I'm also going to use the excuse of it being public but not
fixed to put some serious time into cleaning and commenting. If you
compare that stuff to my latest GitHub project, Clock Signal, it's a
world of difference. I know programmers often wince when they look at
their own old code but the thing that jumped out as really
embarrassing looking back briefly after uploading was a split
infinitive.

Also, I always find going back and commenting to be a good way to get
back into a project. I might finally managed that Freescape-style game
I've always wanted to write.

GitHub and a polygon filling routine

[Thomas Harte]

Quite probably not of any particular interest to most of the group
since it's mostly a rehash, but because I'm about to spend quite a lot
of the year country hopping I've slightly selfishly started dumping a
whole bunch of my old projects onto GitHub as a kind of free backup.
That means that you can now find almost exactly the same 3d engine as
I released previously at http://github.com/TomHarte/Sam-Coupe-3d

As set up, a build will just do exactly what the previous release did.
So, amongst other things, it's still pyz80 based and should still
build to the same demo as shown in
http://www.youtube.com/watch?v=wTpbITdRHl0 , which anyone interested
has probably already seen.

Potentially of interest though, and hopefully justifying the repost,
is the inclusion of my best effort to date at a solid convex polygon
filler in 
http://github.com/TomHarte/Sam-Coupe-3d/blob/master/src/lib3d/drawpoly.z80s

I'm aware there were some preliminary experiments in filled 3d on the
compilation disk I released a while ago but this filler is entirely
unrelated and significantly more efficient. It uses the run-slice
variant of Bresenham, an edge table and an SP-facilitated span filler
(so, disable interrupts temporarily unless you want occasional random
pixels left on screen). It doesn't perform any pixel-level clipping so
to use it in 3d proper you'd want to clip to the frustum. The code
already has frustum clipping for vectors so the main issue would be
avoiding repeat calculations on shared edges, though I think I
eventually came to the conclusion that the smartest thing would just
be a cache rather than an elaborate data structure.

Re: Single pixel hardware scroll?

[Thomas Harte]

The weird thing then is that the article claims the effect can be triggered by 
border changes in the invisible part of the screen. Though I guess the screen 
he had probably just had a large amount of the tube hidden from the eye. The 
idea that border colour changes can somehow insert an extra 64us delay and an 
hsync does seem basically ridiculous but I thought it better to ask.

At least per the spec, TVs don't have any logic for alternate frames. Whether 
the next is even or odd depends on whether the long sync ends in the middle of 
a scan line or at the end. So computers like the Sam, with a rigid sync 
schedule, explicitly output a non-interlaced display only. However, modern TVs 
- even some late model CRTs with digital sync generators - often emulate that 
incorrectly, and emulator authors tend to be quite parochial and superstitious 
about this stuff for some reason, hence e.g. the mostly invented black scan 
lines a lot of them like to insert.

On 2 Feb 2012, at 10:24, Geoff Winkless sam-us...@geoff.dj wrote:

 On 1 February 2012 20:42, Simon Owen simon.o...@simcoupe.org wrote:
 On 01/02/2012 20:07, Thomas Harte wrote:
 I notice that whatever effect it thinks it is relying on doesn't work
 in Sim Coupe.
 
 It's certainly nothing that's implemented at the moment, but if it's
 shown to be a real effect (like border pixels), it should go in.  Though
 it does feel like it could be specific to CRTs, and more likely those
 that suffer from distortion due to intensity differences?
 
 I know the TV I first used would exhibit something similar. I wouldn't
 have thought you could ever rely on it though. Certainly the 8833 I
 ended up with wouldn't do it.
 
 I remember there being some sample interlaced SAM pictures, which may 
 have relied on the effect to give the necessary vertical shift to help
 with colour blending.
 
 I thought that was just about the fact that the TV would display
 alternate lines each 50Hz - so you could switch screens between two
 and effectively double your Y resolution, the problem being that you
 could never tell which would be the top and which would be the
 bottom.
 
 If you're thinking of playing with stuff like that in SimCoupé, how
 about adding in a screen start address OUT mod? I'd love to see what
 could have been done with just a small change to the ASIC design :)
 
 Geoff

Re: Single pixel hardware scroll?

[Thomas Harte]

I'm sure I'm just repeating what you already know but...

They're accurate for (most) aperture grille CRTs but completely
inaccurate for shadow mask CRTs. Sony had aperture grilles patented
for its Trinitron screens right up until the late 90s so they're a
tiny minority, especially of televisions contemporaneous with things
people commonly emulate so as to look original.

You're right about the softening though in the circumstances you
specify — I had in my head the emulators that chuck a huge
high-contrast complete pixel wide line in between every line of real
pixels, just adding yet more unrealistic contrast. I guess a proper
emulation would separate luminance and chrominance, filter the two
separately and the latter much more aggressively, then apply a
weighted sampling that simulates a shadow mask. You could do it all on
the GPU relatively easily.

On 2 February 2012 11:12, Simon Owen simon.o...@simcoupe.org wrote:
 On 2 Feb 2012, at 10:43, Thomas Harte wrote:
 emulator authors tend to be quite parochial and superstitious about this 
 stuff for some reason, hence e.g. the mostly invented black scan lines a lot 
 of them like to insert.

 I find a partial scanline effect helps soften a harsh pixelated image, and 
 reduce the softness of the filtering done during stretching with some video 
 drivers.  So even if they're not technically accurate I find it somehow looks 
 a bit more balanced than the pure image.  There's probably also an aspect 
 that it makes it look more generated, which fits with the feel of being 
 emulated — so you're probably right!

 Si

Re: Single pixel hardware scroll?

[Thomas Harte]

 a) tell the difference between a normal address request and an ASIC request

Is the z80's MREQ line available to peripherals? I forget whether
that's active during refresh cycles but it would probably give the
game away. Alternatively, the WAIT line probably gives something of
the game away.

Re: Single pixel hardware scroll?

[Thomas Harte]

Having checked, the full complement of z80 lines are on the expansion
connector so it wouldn't be a problem to figure out when the z80 is
accessing memory. That being said, if the ULA fetches aren't there
then there would appear to be a problem.

Maybe a smarter plan would be something that plugs into the memory
expansion port at the bottom? It's obviously completely feasible from
a hardware point of view that you could fit a modified 256 kb
expansion with some memory-mapped registers (as I can't find a pinout
for that so I'm not sure if IOREQ is down there) so that, if enabled
by pushing a suitably arcane initiation sequence (as per the precedent
of the CPC+), you can subsequently specify a 16 or 18 bit memory
offset that's added to the incoming address (overflow being lost if
you go 16 bit, I guess) before that section of RAM is accessed.

So you'd need to keep your program code in the internal 256 kb, and
then you'd be able to use the other 256 kb for hardware scrollable
screens.

On 2 February 2012 12:47, Thomas Harte tomh.retros...@gmail.com wrote:
 a) tell the difference between a normal address request and an ASIC request

 Is the z80's MREQ line available to peripherals? I forget whether
 that's active during refresh cycles but it would probably give the
 game away. Alternatively, the WAIT line probably gives something of
 the game away.

Re: JAM Assembler 1.13 problems?

[Thomas Harte]

I was too young to appreciate it at the time but I think Fred had a great 
series on assembly and the Sam that flowed into the sort of topics specifically 
of interest to game writers. Has anyone converted those to a modern document 
format?

Other than that I can tell you that z80 questions tend to get answered very 
quickly and in a good amount of detail on StackOverflow though one appears only 
once every other month or so, so it's not much of a learning resource.

On 1 Feb 2012, at 10:39, war...@wdlee.co.uk wrote:

 On a related but slightly different note... Sometime in the near future, I 
 want to get back into a fairly major SAM gaming project I was working on. I'm 
 going to give JAM a go (Just quickly tested it on my machine running Windows 
 7, and seemks to work fine!). :-) I made the mistake of working in 
 GamesMaster again when I started it last year, but I hit a bit of an annoying 
 brick wall with it (Yes, I know... but it worked so well for my first few 
 games! :-D ) Unfortunately those limitations AREN'T because of the 
 limitations of the SAM, so I don't want to compromise the game from what it 
 could do, simply because of GamesMaster.
 
 So my plan is to re-program it in Assembly. And my question is... (I think I 
 may have asked this before, but for the life of me I can't remember, so sorry 
 if I have!) what's the best resource for learning it?? ;-)
 
 Dave, I love what you've done with Dave Invaders :-D What did you read for 
 learning how to program it?
 
 Quoting Balor Price toberm...@cookingcircle.co.uk:
 
 Ah.  I am a moron.  Updated from Java 6 update 21 to update 30 and the 
 problem went away.
 
 Must say, though, I would never have expected that to have been a problem, 
 especially because your binaries are all JAR files instead of JAD midlets.  
 Okay I'm confused again now!
 
 Howard
 
 
 On 01-Feb-12 07:59, david brant wrote:
 People do use it then, not had much in the way of feedback.
 
 Jam Assembler does not doing anything special with the font or anything 
 like that. It would be using Windows API for fonts and messages etc. i.e. 
 anything standard windows stuff.
 
 Jam Assembler not been tested on anything newer than XP though.
 
 What version of Java is your computer using? Have you tried re loading Jam 
 Assembler? I have a newer version on my computer which sorts out some 
 project view issues and does method inheritance I'll upload it tonight with 
 a bit of luck.
 
 Otherwise can you send me a screen shot please.
 
 On 1 Feb 2012, at 01:19, Balor Price wrote:
 
 
 So, hmmm... while I'm fired up...
 
 Anyone having problems with the GUI in Jam Assembler?  It's been a while 
 since I tinkered, but now I'm getting gobbledygook instead of English in 
 the dropdown menus and dialogue boxes... At a guess I'd say the font 
 lookups had gone askew, it's a JAR file that's executed so it's not 
 relying on Windows API calls or anything.  David?
 
 Howard
 
 
 
 
 

Single pixel hardware scroll?

[Thomas Harte]

I thought this was worth discussing separately but in the JAM
Assembler conversation earlier today Andrew Gillan provided a link to
http://sam.speccy.cz/ , on which one of the documents is
http://sam.speccy.cz/coding/hardware_scroll.txt — which alleges that
changing the border rapidly between black and white can affect the
position of the pixel area within the television frame by a row. Sadly
it doesn't bother to explain what aspect of the hardware it thinks is
responsible or to provide any real timing information, preferring to
talk at great length about how a single pixel hardware scroll would
buy you two frames to update the display rather than one if you wanted
a scrolling area. It's also weirdly specific to a particular monitor
in one place, and I notice that whatever effect it thinks it is
relying on doesn't work in Sim Coupe.

Can anyone comment on whether the article documents a real Sam
hardware effect rather than merely a perceived effect specific to a
particular monitor?

Re: New Game - Dave Invaders

[Thomas Harte]

I'm not really sure exactly where the age divide falls on this issue
and I'm willing to bet none of us is classically young, but yeah!
Let's either show them or allow ourselves to be shown, as applicable.

I keep meaning to do some Sam work again, but getting started always
feels like a huge effort — what tool chain did you use for Dave
Invaders?

On 29 January 2012 10:52, Andrew Gillen a...@joua.net wrote:
 Yep and show us youngsters how it is REALLY done :)


 --
 From: Chris Pile chris.p...@blueyonder.co.uk
 Sent: Sunday, January 29, 2012 10:48 AM

 To: sam-users@nvg.ntnu.no
 Subject: Re: New Game - Dave Invaders

 Have to send a me too post - really impressed. Love the graphics.
 That's two good new SAM games in the last year (Rob's Garden Centre
 Of The Universe game being the other one) - what's going on?!


 I agree 100%!  It's quite worrying...  But inspiring all the same.  Maybe
 it's time for us
 old dogs to dust off our assemblers and get coding!!  :-)

 Chris...

Re: New Game - Dave Invaders

[Thomas Harte]

I'm also going to out myself as a fan — though it took me about five
goes to get to the second screen! As a career non-finisher I also have
to agree with Andrew's comments on seeing a project through.

My only observation would be that sometimes the collectibles aren't
obvious because of the nice, detailed and colourful backgrounds. Is
there any way they could periodically do a little sparkle or
something?

And would attempting to prod you towards an open source release have any effect?

On 28 January 2012 11:41, Andrew Collier and...@intensity.org.uk wrote:
 On 27 Jan 2012, at 13:49, Andrew Gillen wrote:

 Hi folks

 I've finished writing my first game for the SAM. In fact it is pretty much 
 the first game I've ever programmed in assembler (certainly on the SAM 
 anyway) . I've tinkered with various high level languages over the years but 
 have nothing to show for it.

 Nice work! I particularly like the graphics. The Sam's 16 colours can be a 
 bit limiting and a lot of games have very sparse backgrounds because of that, 
 so it's great to see yours with lots of detail and different themes.

 Most especially though, congratulations for taking a project and seeing it 
 through until its released. I know from experience how difficult this can be.

 Andrew

Re: Floppy drive problem

[Thomas Harte]

MGT sold an external interface to allow connection of standard floppy drives, 
including those used with the Disciple and +D interfaces and pretty much every 
other home computer - possibly you could locate one of those? It looks like a 
PC drive should attach.

On 19 Jan 2012, at 21:24, Aleš Keprt a...@keprt.cz wrote:

 I would rather sell the whole computer than to invest more money to it.
 Anyone interested?
 (For collectors: I still have also the original cartoon/polystyrene box. :-))
 
 I do have a plenty of working PC floppy drives at home, but I think it would 
 be more wise to move to the compact flash instead of putting more money to 
 new floppy controllers.
 
 /---
 Aley
 
 -Původní zpráva- From: Colin Piggot
 Sent: Thursday, January 19, 2012 10:12 PM
 To: sam-users@nvg.ntnu.no
 Subject: Re: Floppy drive proble
 
 Thomas wrote
 the original MGT SAM Coupe diskdrives are from Citizen, they are indeed a 
 bit different than PC drives. One possible way is to get a replacement
 drivebelt, or buy a replacement diskdrive, both can be ordered from Quazar: 
 http://www.samcoupe.com/
 
 I don't have any original Citizen drives left, and no drive belts at the
 moment.
 
 I can provide a new disk drive system based around a modern PC disk drive
 and an interface board (which I can supply on it's own without a disk drive
 if you already have a spare PC drive to hand)
 
 Colin
 
 =
 Quazar : Hardware, Software, Spares and Repairs for the SAM Coupé
 1995-2012 - Celebrating 18 Years of developing for the SAM Coupé
 Website: http://www.samcoupe.com/
 

Re: Power supply circuit diagram

[Thomas Harte]

You should sell those; some of us are pathologically incapable of
soldering but would love a quiet power supply.

On 14 January 2012 09:39, Leszek Chmielewski retr...@gmail.com wrote:

 No, but my PSU was very loud after few minutes, so I adopted a normal
 +5V/2A +12V/2A PSU by soldering the SAM PSU connector to it. Works
 excellent!
 In the manual they state which pins are GND, +5V and +12V, so it is very
 easy and modern PSU are smaller and stronger.

 LCD

 2012/1/14 Aley Keprt a...@atlas.cz


 Hi guys, does anybody have the original Sam Coupe power supply unit
 circuit diagram?
 My power supply was damaged years ago and somebody repaired it by
 replacing something inside with an old big zener diode. I just remember that
 12V line was dead and that diode is just a random one which we were able to
 get. Then in 90's it was not easy to buy good new diodes here, but it is
 easy to buy anything on internet now. So I just need to know what was the
 original piece in the PSU and I am going to replace it back.
 Thanks in advance.
 Aley Keprt

Re: SimCoupe Speed

[Thomas Harte]

Roger: I've never had an external RAM module and have never written a
program that requires the storage so I'm not talking from firsthand
experience. If you've tried it and encountered problems then I
probably can't help.

Simon: cool, sounds good. So it's just another clue (albeit quite an
authoritative one, with DirectSound at least) as to correct timing
rather than an absolute authority? Or maybe that's stating things too
vaguely and a better description would be analogous to a clock
multiplier sort of setup? The 2048/44100 comes in and you're saying
'so I'll push another frame at what I think is however-many hundredths
of a second from now, another at about 1/50th of a second after that
then wait for the next pulse'?

Sorry for the extended off-topic questions — I'm working on some brand
new emulation stuff myself, on and off, so I'm quite interested at the
minute.

On Tue, Oct 25, 2011 at 2:47 PM, Roger Jowett rogerjow...@gmail.com wrote:
 in the bottome 32k yes where the romspeccy screen$ are
 but can the emulator explosion program be modified to do it? it
 already sdetects teh external ram

 On 25 October 2011 14:02, Simon Owen simon.o...@simcoupe.org wrote:
 Yes, you could certainly fill the top 32K with faster external RAM.  Though 
 using Spectrum-compatible mode 1 does add extra contention stripes, so 
 you'll still get an extra hit on accesses in the bottom 32K.

 The current SDL version of SimCoupe uses 2048 samples, so it must have been 
 what I found as the best behaving too!  Though I've always found SDL sound 
 more awkward to work with as it requests extra data as needed, rather than 
 providing a method to check the level and add more.  I'm expecting to use a 
 mix of time stamps and buffer requests to trigger the next frame at the 
 right point, which should solve the 22-syncs issue you mention.  It's a lot 
 easier with DirectSound as you have tighter control over the play+write 
 cursors, so you automatically get sub-frame accuracy (or you certainly used 
 to – I've not checked with Vista or later).

 I have an occasionally worked on source branch that's moving towards doing 
 that, though there are a number of related complications to untangle first.  
 One day...

 Si


 On 25 Oct 2011, at 13:18, Thomas Harte wrote:

 I think I'm right to say that external RAM can be paged into the top
 32kb of address space. And it's presumably uncontended? So you could
 page some in and run a 48 emulator but everything would run at quite
 the wrong speed.

 Simon: I've always found 2048 samples to be the sort of level where
 most operating systems start playing nice with audio output; assuming
 44100Hz output, wouldn't synchronising to that limit you to only about
 22 synchronisation points a second? So frames would end up bunched
 together?

 Not really on topic, I admit, and the evidence that you know what
 you're doing is plentiful. I'm just curious.

 On Tue, Oct 25, 2011 at 12:38 PM, Roger Jowett rogerjow...@gmail.com 
 wrote:
 key repeats?

 is it impossible to run 48 emulator snapshots in external ram?

 On 24 October 2011 14:35, Simon Owen simon.o...@simcoupe.org wrote:
 Hi Ian,

 I'm hoping fixed running rates will come 'for free' as part of the switch 
 to audio-based synchronisation (rather than the current timer method).

 In the meantime, if you don't actually need the key repeats, try this 
 patched ROM to disable them:  http://dl.dropbox.com/u/2553707/norepeat.zip

 Extract it somewhere, then select it from Tools - Options - System 
 (tab) - ROM image.  Reset the emulated machine to activate it.

 Cheers,

 Si


 On 23 Oct 2011, at 10:33, Ian Spencer wrote:

 Hi Si,

 I'm sure you have been asked this hundreds of times before so I'll 
 apologise before I start but I've always used SIMCOUPE synchronised to 
 50Hz with most programs and with others unsynchronised where the speed 
 was useful (especially with the program which I have used for years to 
 handle my bank accounts) and set the keyboard repeat rate to prevent 
 multiple key presses being produced. But the modern 3Ghz 4CPU machines I 
 now have are just so fast it's impossible to set the repeat rate low 
 enough. They are just too fast and as many programs are much more usable 
 when the speed is 200 -  500% above the standard it would be really 
 fantastic if this was in some way selectable even if at this speed the 
 instruction timings weren't very accurately scaled.

 Best wishes,
 Ian Spencer

Re: Resistor R55

[Thomas Harte]

I hadn't considered that bright might be variable by channel — I'll
have to check that out.

If it were MC1377P affecting all channels then presumably I'd see the
effect only through the aerial or a single-line video output? If I
were to find a suitable RGB scart cable then I'd still get the
expected output?

Re: the ASIC and primarily because I'm curious, how would making a
replacement for that work? Are there readily available FPGAs that
could drop straight into the same slot, if not then how expensive is
it to build some sort of bridge? As I said, I'm quite an electrical
dunce so don't hesitate to be patronising.

Given that at least some of my bright comes and goes, my floppy drive
seems to be dead (it makes a spinning noise and lights up but fails to
report that a disk is inserted) and there's a real chance I may
emigrate soon it might be time for me to put my real SAM away for
good. That'd be a little sad.

On Tue, Oct 4, 2011 at 10:11 AM, Leszek Chmielewski retr...@gmail.com wrote:


 2011/10/4 nev young pasiphae1...@yahoo.co.uk

 On 03/10/11 23:40, Andrew Collier wrote:

 On 3 Oct 2011, at 16:22, Thomas Harte wrote:

 It looks like a previous owner of my current SAM has had occasion
 to replace resistor R55, or at least, to solder an additional copy
 of R55 on top of the existing one. See
 http://postimage.org/image/1g4kbz490/

 Immediate follow-on questions, mostly resulting from me being an
 electrical dunce, are: what does R55 do, what would be the likely
 effect if it was a bit dodgy and is it really okay just to solder
 an extra resistor on top of an existing one?

 According to the schematics in the tech manual, R55 is doing
 something to do with the MIC tape interface, and should be a 100kΩ
 resistor - which if I'm reading the photo correctly (the colour bands
 look {brown, black, yellow, gold}) is exactly what it is.

 Two of them wired in parallel are equivalent to a single resistor of
 50kΩ (assuming they both work) though I'm not certain what the
 implication of that is for the rest of the circuit.

 R55 and C28 form a feedback circuit that should square up the audio
 signal coming from the tape cassette.  Reducing R55 from 100K to 50K, by
 putting two in parallel, will increase the amount of feedback.

 The Bright signal is generated by the ASIC and appears on pin 18 (If I
 read my diagram correctly). It then goes to R65, R69 and R73 (all 36K
 [orange, blue, orange stripes]) to drive each of the colour driver
 transistors M3(green), M4(red) and M5(blue) (3x BC547).

 If you have lost bright on one colour look at the corresponding resistor
 and PCB connections. If the transistor has blown you would lose that
 colour completely. If you have no bright on any colour then check the
 output of the ASIC and the PCB connections from there to the 3 resistors
 for cracks, dry joints, broken through plating etc.

 If there is no signal coming out of the ASIC then get used to a dull
 life. :-(

 Nev

 My SAM has no BRIGHT too. There was a shortcut between Composite and +12V,
 so the MC1377P was burned out (Just got a replacement by desoldering a Atari
 Mega STE), I lost BRIGHT too as the ASIC was toasted a little too. After
 replacing it with ASIC from my spare SAM the BRIGHT is back again.
 It is time to design a replacement ASIC. Velesoft is working on one since
 years, but he is too ambitious: 4096 Colours, Hardware sprites and
 scrolling...
 LCD

Resistor R55

[Thomas Harte]

My SAM has an intermittent fault involving the 'bright' palette bit
having no effect. In reality it seems to be so intermittent now that
I'm not sure I still have a problem but nevertheless I thought I'd
open the case and clean out any dust, etc, since even my very low
level of electrical competence leaves me aware that intermittent
faults can be related to heat and the accumulation of dust creates
heat problems. I know the SAM doesn't have any fans to collect dust
and operates at a very low temperature but since it doesn't take a lot
of effort to check I thought I'd have a glance.

It looks like a previous owner of my current SAM has had occasion to
replace resistor R55, or at least, to solder an additional copy of R55
on top of the existing one. See http://postimage.org/image/1g4kbz490/

Immediate follow-on questions, mostly resulting from me being an
electrical dunce, are: what does R55 do, what would be the likely
effect if it was a bit dodgy and is it really okay just to solder an
extra resistor on top of an existing one?

Re: Sam Hardware / Software for sale and some disks free

[Thomas Harte]

I've wanted to see DRiVER for a while, having read the first three
Inside Macintoshes a few years ago and the Smalltalk-80 book a little
before that. It'd be interesting to play about with.

But how does sellmyretro work? I notice the items listed as bids
rather than purchases aren't also on eBay, so it presumably has its
own auction system? The entire selfish question I'm building up to is:
I'm not in the UK right now, and won't be for a bit more than a week
after the auctions end; would you be so willing and is sellmyretro set
up so that, if I were to win any, I could ask you not to post my items
for a week?

On Fri, Aug 26, 2011 at 2:23 AM, Rich Mellor r...@rwapservices.co.uk wrote:
 Good evening,

 I have listed a few bits of SAM hardware and software on sellmyretro.com -

 http://www.sellmyretro.com/category/All+categories/Retro+Computers/SAM+Coup%C3%A9

 I also have 7 SAM formatted floppies free to a good home (for the cost of
 postage) - they have various hand written labels on them, including
 Electronic Calculations, Games, Eyeconiac + Z8 Demo (I think!), Graphics,
 and Hacker Text.

 If anyone wants them to have a mooch through, let me know before they go in
 the bin!

 --
 Rich Mellor
 RWAP Services

 http://www.rwapsoftware.co.uk
 http://www.rwapservices.co.uk

 -- Try out our new site: http://sellmyretro.com

Re: Accessing Sam formatted disks through a USB floppy drive

[Thomas Harte]

On OS X, which of course has a BSD-derived layer, I wasn't able to get
anything using dd — my USB floppy drive showed up as a block device
and exposed only the PC-style double density sectors as blocks. I was
able successfully to image any disk that didn't use any of its
tenth-per-track sectors, but that's the full extent of it.

The Kyroflux, at about £80, doesn't actually look like a bad deal, but
can I attach a Disciple/+D drive to it? It looks to be the same sort
of connector, and to match the one I had on my Acorn Electron +3
(equivalent) cartridge, but is it?

On Fri, Jul 22, 2011 at 9:54 AM, nev young pasiphae1...@yahoo.co.uk wrote:
 On 22/07/11 15:38, Dicky Moore wrote:

 Hey all

 Has anyone had any luck in copying Sam-formatted floppy disks to .dsk or
 .mgt images using a USB floppy drive?

 Very little hope of doing that.

 All the programs I've seen, or written myself, need to access the floppy
 disk controller which you usually can not do through usb.

 If your PC has a floppy controller I would suggest connecting a floppy drive
 directly to that, (possibly hanging out of the side and balanced on a pile
 of books) to do the copy. Then put your machine back together again.

 If you really want to use the usb floppy drive then if you're feeling very
 strong hearted you might try running a linux system and using the dd
 utility. Something like:
 dd noerror if=/dev/fda of=~/image.txt

 Tell it to ignore errors, as on a 1.44Mb disk it will expect 18** sectors
 per track. So the last 8 will error. I've never tried this so can not vouch
 for if it would work. Even if it does you'll have to play about with the
 image to make it usable.


 ** I think a 1.44Mb disk has 2 sides of 80 tracks with 18 sectors of 512
 bytes but I may be wrong.

 Nev

Re: Sam Coupe Testing

[Thomas Harte]

Sorry, I don't know most of the answers and am probably not about to
be entirely helpful but since there don't seem to have been any other
answers...

 I have replaced the TV lead from inside the power unit, and I get a picture on
 my TV.

 However, if the TV is tuned in properly - I get a black and white picture,
 otherwise the start up screen is very blue.

So there's no way to get colour at all (other than a whole-screen
tint)? I remember there being some sort of hardware fault that can
cause that — it happened to my original Sam Coupe and we ended up
sending it back under the warranty. I think they must just have
shipped a new unit, since I remember the disk light changed colour
too.

That said, it's very that's a completely unrelated story.

 There were two SCART leads with the computer, but neither seem to give an 
 output.

 I seem to recall reading that the SCART is very different to normal.

 Does anyone have spare SCART and cassette leads please?

Colin can generally sell you those things if that's acceptable — his
website is http://samcoupe.com/ and both composite and RGB scart leads
are £9.99.

 Also - I have found a semi-circular rubber foot - I presume that the Sam 
 should
 have four of these in the holes on the side of the casing?

 Does anyone have some spares?

Yep, should have four, usually blue but sometimes black. I've no ideas
about spares.

 My Sam has 512K memory, with piggy-backed RAM chips and a wire which runs 
 across
 and is connected to one of the pins on the internal expansion port (to the 
 right
 of the disk drive).

 Is this normal - as it seems an awkward way of connecting it!

No, that's probably some sort of do-it-yourself modification. I've
never actually fitted one, but I think the official upgrade is just a
tiny daughterboard that you plug in after unscrewing the little panel
with copyright information/etc on the bottom to reveal the relevant
hole.

 Finally, I have an MGT mouse interface for the Sam, and a Comms interface - 
 what
 is the best way of testing these?

The mouse interface expects an Atari ST-style serial mouse, so you'll
need to get hold of one of those. It came with a demo disk including a
mouse-driven version of Flash! and some code to access the mouse from
your own BASIC programs. It's not the same thing but you can get the
'Mouse Driver 2.0' disk from http://www.worldofsam.org/node/214
legally, as distribution rights have been granted. A bunch of PD
software that supports it is also available.

As for the comms interface, I've no ideas specific enough to be helpful.

Re: Contention and JR instruction timing.

[Thomas Harte]

Apart from a desire for part uncontended memory (ala the Spectrum) and
a hardware scroll, a simplified blitter would have been advantageous
(eg, give it start address, end address, length, tell it to go and
then it replaces the z80 on the bus until the copy is complete; even
with the CPU having to do a lot of lifting around the outside and run
some other logic that'd give you a 25fps scroll if that's what you
wanted it for, or filled vectors if you prefer).

Failing that, I really don't think video adjust registers could have
cost that much. So you've a horizontal register and a vertical
register, each capable of taking values in the range 0 to 7 and will
offset the pixel output by that amount on the screen. They're timing
delays on the video output, essentially, but they buy you up to 8
frames of scrolling with very limited redraw costs, and that gives you
enough time to prepare the next major offset on a secondary screen. If
memory serves, you get a similar thing for free in the 6845 that
appears in the BBC, Amstrad and VGA adaptors.

Standard comments about hindsight apply, of course.

On Tue, Apr 26, 2011 at 12:46 PM, Geoff Winkless sam-us...@geoff.dj wrote:
 On 26 April 2011 10:55, Chris Pile chris.p...@blueyonder.co.uk wrote:

 Mmmm, not sure I would have like hardware scrolling to be honest.  It
 would probably
 have meant a glut of scrolling marioesque platform games.  Which - for me
 - is a whole
 lot less desirable than infinite ball demos!

 Yes, scrolling platformers become possible, as do scrolling shoot-em-ups
 (doing it in Mode 2 doesn't count), but it also means you can open up to
 innovative stuff like Thrust and Exile that would never have been possible
 on a 2MHz processor. You also get much more responsive text editors, basic
 editors etc.


 Some sort of blitter to chuck large blocks of data around at high speed
 would have been
 a *very* nice addition.  That 24k screen really is too much for the old
 Z80 to cope with!

 Eugh... _another_ thing to add to Simon's memory contention list? :)
 A blitter would have been costly both in terms of electronics and in terms
 of memory T-states. When I said free I meant it - a single OUT statement
 could set the memory start address and everything else would have stayed the
 same, with the extra port taking the ASIC equivalent of a couple of sets of
 gates. I guess the current screen address currently just gets reset to 0
 every frame - but if you wanted to save the extra electronics required for a
 screen address register you could make it so the software had to reset it
 every frame interrupt. Actually that's silly, there wouldn't need to be any
 per-frame reset logic, just some logic so that when when bits 13 and 14 are
 both set they're both immediately cleared (0x6000 - 0x)
 On 26 April 2011 10:54, Simon Owen simon.o...@simcoupe.org wrote:

 Just those two could have made a huge difference to what was possible.
 *sniffs*   I do vaguely remember Simon Goodwin explaining why SAM missed out
 on hardware scrolling, but I can't remember the details.  I think it was
 something RAM access related, so perhaps the change to use dedicated VRAM
 would have made it easier?  As a hardware n00b I've no real idea!  Anyone?


 I don't see how changing the start point within a 24k rolling window would
 make any difference to the RAM timing - you still have to access the same
 data the same number of times and at the same rate.
 My hardware experience is pretty limited though, so I'm not going to start
 contradicting Mr Goodwin.
 G

Re: Contention and JR instruction timing.

[Thomas Harte]

 Umm... Well you can't read and write the same byte in the same cycle; but
 you're right, if the 79000 frames figure is correct that would be usable.
 However I'm not sure it is: system clock is 6MHz, so 6M T-states per second,
 that's 120,000 every frame (6M/50). That's about 30,000 memory cycles in
 screen-off.
 If you were going to invest in significant graphics hardware you'd be better
 off with scalable hardware sprites that aren't in system memory at all and
 having a 4-colour screen and using full 128-colour sprites for the
 interesting stuff. Admittedly they don't help you with 3d but at least you'd
 have half the memory to move around and half the contention to worry about.
 G

Well, no, that's why I costed for doing the full screen twice in two
frames — a read and a write, plus some useful CPU time (even after
drawing a new row or column of pixels so that it's a scroll), at
25fps. Though I think your main point is correct; if graphics ability
were the main objective then you'd be looking at a quite different
route, not a bunch of little tweaks or minor additions. And we're told
that a selectable screen start address was considered but not possible
in the current design, so the real question is what else do you
jettison and how do you do it within the constraints beyond mere final
manufacturing cost. It's an interesting thought experiment, but it is
predicated on one particular aspect being elevated in importance in
such a way as to violate the original design goals.

Vaguely related: has anybody here ever played with one of those FPGAs?

Re: Contention and JR instruction timing.

[Thomas Harte]

On Tue, Apr 26, 2011 at 4:58 PM, Chris Pile chris.p...@blueyonder.co.uk wrote:
 Besides, there's something *pure* about having a chunk of RAM and a CPU -
 and not much else!

While it's pure, and the basis for some of the great machines — the
Spectrum, obviously, but also the ST, sort of the VGA-era PC and the
original Mac (with an extra end-of-scanline byte fetch pushed to a
speaker, to give ~2Hz sampled sound output for almost free!) — I
get a similar kick out of the modern, programmable GPUs. Though I
guess they largely compartmentalise the RAM + [heavily parallel]
processor bit and leave the rest of the system to whatever it likes.

I think I'm becoming a big fan of parallel programming in general. I'm
very glad I did some LISP stuff at university; not sure how I'd take
to it if I was coming over from the purely procedural world.

Cables for a composite PAL monitor?

[Thomas Harte]

As someone who doesn't care enough about TVs to do anything but accept
hand-me-downs and other bits of charity, I've just received an old
plasma from work. But the catch is that it's a decade old and is
better described as a monitor than a TV, built for the international
market. So, in addition to VGA and DVI, it has composite and component
inputs and can accept a PAL or NTSC signal but has no tuner and no
SCART socket. It has an S-Video socket, a bunch of phonos and those
other things that I don't know the name of, but look like a bit like
phonos except that they stick out further and seem to have a smaller
hole. They're for component input; it's a normal yellow phono for
composite. Lacking another connector, I assume it's sync-on-green.

Obviously the SAM can output RGB and composite from its
not-quite-SCART socket, but what can I do to connect it to my TV?
Quazar doesn't seem to have anything relevant in stock and I'm a
soldering dunce.

Re: Cables for a composite PAL monitor?

[Thomas Harte]

Yes - lots of those, including two next to the composite video. The
screen is comically oversized if anything, and they seem to have taken
the opportunity to really cover the thing with inputs...

Probably best to get in touch privately and sort this out. I'm finally
about to scramble desperately onto the housing ladder, so depending on
timings I may even have a new address to report.

On Monday, April 18, 2011, Colin Piggot qua...@clara.net wrote:
 Thomas wrote:

  it's a normal yellow phono for composite.

 Obviously the SAM can output RGB and composite from its
 not-quite-SCART socket, but what can I do to connect it to my TV?
 Quazar doesn't seem to have anything relevant in stock and I'm a
 soldering dunce.


 But I do make up customised cables on request :)

 I can build a cable to connect from the SAM SCART socket to a phono plug for 
 your TV's Composite Video input. Also, I assume there is red and white phono 
 sockets for audio input too?

 Colin
 =
 Quazar : Hardware, Software, Spares and Repairs for the SAM Coupé
 1995-2011 - Celebrating 17 Years of developing for the SAM Coupé
 Website: http://www.samcoupe.com/

Re: Dizzy (was:Porting spectrum games...)

[Thomas Harte]

LZMA doesn't seem to be terribly well documented, but I'm curious so
do you mind if I ask a few questions?

The LZ77-style stuff is quite well documented on Wikipedia, with
variable packet sizes but otherwise unremarkable. Though it looks like
length of repetitions is limited to 273 at most and the maximum
distance isn't particularly clear. I guess for Sam screen purposes,
273 is more than enough and 15 bits for distance is always more than
enough, with fewer bits being an option?

Then there's the range coding aspect. It looks like the individual
LZ77 packets are range coded and the fixed values encoded in literal
packets are range coded separately? So you end up with two streams and
you follow the LZ77 stream, grabbing a decoded digit from the data
stream whenever you hit a literal packet?

There are vague references to context and Markov chains without much
exposition — I've taken this to mean that you've not just one table of
symbol probabilities, but you divide them into groups and each group
uses a separate table of probabilities recording what may come next.
Those probabilities are then used for the range coding. And it's
implied that group membership is indicated by the value of a certain
number of the most significant bits in the normal LZMA course of
things, presumably to make the probability tables cheap to transmit.

Is that all correct? Or even close? It's all much more clever than
anything I was trying.

On Tue, Aug 3, 2010 at 9:11 PM, Adrian Brown
adr...@apbcomputerservices.co.uk wrote:
 Im using an LZMA approach similar to that in 7-zip - ive nearly finished 
 moving the code out of my project stuff so i can send it over.

 Adrian

 -Original Message-
 From: owner-sam-us...@nvg.ntnu.no [mailto:owner-sam-us...@nvg.ntnu.no] On 
 Behalf Of Thomas Harte
 Sent: 03 August 2010 18:16
 To: sam-users@nvg.ntnu.no
 Subject: Re: Dizzy (was:Porting spectrum games...)

 I've just been reading about range/arithmetic coding, which feels like
 it should do better than Huffman but seems to require some modulo
 arithmetic per input or output token so may not be time effective on a
 Sam. Have you been using anything like that?

 On Mon, Aug 2, 2010 at 12:43 PM, Thomas Harte tomh.retros...@gmail.com 
 wrote:
 It'll be interesting to see how you've done it. If code overhead is an
 issue then you've obviously taken quite a different approach to me.

 I had a quick poke around on Amazon for textbooks on this sort of
 thing but ended up preordering a Kindle. So that's my book budget gone
 for the next couple of months...

 On Sun, Aug 1, 2010 at 1:46 PM, Adrian Brown
 adr...@apbcomputerservices.co.uk wrote:
 Ill extract it from the code that I cant send and put it in its own project 
 is C first

 Adrian

 -Original Message-
 From: owner-sam-us...@nvg.ntnu.no [mailto:owner-sam-us...@nvg.ntnu.no] On 
 Behalf Of Stefan Drissen
 Sent: 01 August 2010 13:31
 To: sam-users@nvg.ntnu.no
 Subject: RE: Dizzy (was:Porting spectrum games...)

 Not a C person, but would http://sdcc.sourceforge.net/ help?

 -Original Message-
 From: owner-sam-us...@nvg.ntnu.no [mailto:owner-sam-us...@nvg.ntnu.no] On
 Behalf Of Adrian Brown
 Sent: zondag 1 augustus 2010 14:04
 To: sam-users@nvg.ntnu.no
 Subject: RE: Dizzy (was:Porting spectrum games...)

 This will be a nightmare to get into z80 ;)  that is the downside. (unless
 you build it using Sam C - it might compile under that) but i think a z80
 version would be required.

 -Original Message-
 From: owner-sam-us...@nvg.ntnu.no [mailto:owner-sam-us...@nvg.ntnu.no] On
 Behalf Of Thomas Harte
 Sent: 01 August 2010 12:16
 To: sam-users@nvg.ntnu.no
 Subject: Re: Dizzy (was:Porting spectrum games...)

 As a quick mea culpa, there was a bug in my code that means the second
 set of figures I had were wrong. I'm back to an average 10% and up to
 15% worse than Adrian.

 On Sun, Aug 1, 2010 at 9:37 AM, Frode Tennebø fr...@tennebo.com wrote:
 On Sun, 01 Aug 2010 10:18:55 +0200, Andrew Park alp...@ntlworld.com
 wrote:

 Back in the days of the Sam there was a screen compressing utility which
 was ok, anyone know where i can find it?

 Lord Insanity's Screen Cruncher

 (ftp://ftp.nvg.ntnu.no/pub/sam-coupe/disks/utils/LordInsanityScreenCruncher.
 zip)?

  -Frode

 --
 ^ Frode Tennebø | email: fr...@tennebo.com | fr...@irc ^
 |  with Standard.Disclaimer; use Standard.Disclaimer;  |





 No virus found in this incoming message.
 Checked by AVG - www.avg.com
 Version: 9.0.851 / Virus Database: 271.1.1/3042 - Release Date: 07/31/10
 20:34:00

Re: Dizzy (was:Porting spectrum games...)

[Thomas Harte]

I've just been reading about range/arithmetic coding, which feels like
it should do better than Huffman but seems to require some modulo
arithmetic per input or output token so may not be time effective on a
Sam. Have you been using anything like that?

On Mon, Aug 2, 2010 at 12:43 PM, Thomas Harte tomh.retros...@gmail.com wrote:
 It'll be interesting to see how you've done it. If code overhead is an
 issue then you've obviously taken quite a different approach to me.

 I had a quick poke around on Amazon for textbooks on this sort of
 thing but ended up preordering a Kindle. So that's my book budget gone
 for the next couple of months...

 On Sun, Aug 1, 2010 at 1:46 PM, Adrian Brown
 adr...@apbcomputerservices.co.uk wrote:
 Ill extract it from the code that I cant send and put it in its own project 
 is C first

 Adrian

 -Original Message-
 From: owner-sam-us...@nvg.ntnu.no [mailto:owner-sam-us...@nvg.ntnu.no] On 
 Behalf Of Stefan Drissen
 Sent: 01 August 2010 13:31
 To: sam-users@nvg.ntnu.no
 Subject: RE: Dizzy (was:Porting spectrum games...)

 Not a C person, but would http://sdcc.sourceforge.net/ help?

 -Original Message-
 From: owner-sam-us...@nvg.ntnu.no [mailto:owner-sam-us...@nvg.ntnu.no] On
 Behalf Of Adrian Brown
 Sent: zondag 1 augustus 2010 14:04
 To: sam-users@nvg.ntnu.no
 Subject: RE: Dizzy (was:Porting spectrum games...)

 This will be a nightmare to get into z80 ;)  that is the downside. (unless
 you build it using Sam C - it might compile under that) but i think a z80
 version would be required.

 -Original Message-
 From: owner-sam-us...@nvg.ntnu.no [mailto:owner-sam-us...@nvg.ntnu.no] On
 Behalf Of Thomas Harte
 Sent: 01 August 2010 12:16
 To: sam-users@nvg.ntnu.no
 Subject: Re: Dizzy (was:Porting spectrum games...)

 As a quick mea culpa, there was a bug in my code that means the second
 set of figures I had were wrong. I'm back to an average 10% and up to
 15% worse than Adrian.

 On Sun, Aug 1, 2010 at 9:37 AM, Frode Tennebø fr...@tennebo.com wrote:
 On Sun, 01 Aug 2010 10:18:55 +0200, Andrew Park alp...@ntlworld.com
 wrote:

 Back in the days of the Sam there was a screen compressing utility which
 was ok, anyone know where i can find it?

 Lord Insanity's Screen Cruncher

 (ftp://ftp.nvg.ntnu.no/pub/sam-coupe/disks/utils/LordInsanityScreenCruncher.
 zip)?

  -Frode

 --
 ^ Frode Tennebø | email: fr...@tennebo.com | fr...@irc ^
 |  with Standard.Disclaimer; use Standard.Disclaimer;  |





 No virus found in this incoming message.
 Checked by AVG - www.avg.com
 Version: 9.0.851 / Virus Database: 271.1.1/3042 - Release Date: 07/31/10
 20:34:00

Re: Dizzy (was:Porting spectrum games...)

[Thomas Harte]

It'll be interesting to see how you've done it. If code overhead is an
issue then you've obviously taken quite a different approach to me.

I had a quick poke around on Amazon for textbooks on this sort of
thing but ended up preordering a Kindle. So that's my book budget gone
for the next couple of months...

On Sun, Aug 1, 2010 at 1:46 PM, Adrian Brown
adr...@apbcomputerservices.co.uk wrote:
 Ill extract it from the code that I cant send and put it in its own project 
 is C first

 Adrian

 -Original Message-
 From: owner-sam-us...@nvg.ntnu.no [mailto:owner-sam-us...@nvg.ntnu.no] On 
 Behalf Of Stefan Drissen
 Sent: 01 August 2010 13:31
 To: sam-users@nvg.ntnu.no
 Subject: RE: Dizzy (was:Porting spectrum games...)

 Not a C person, but would http://sdcc.sourceforge.net/ help?

 -Original Message-
 From: owner-sam-us...@nvg.ntnu.no [mailto:owner-sam-us...@nvg.ntnu.no] On
 Behalf Of Adrian Brown
 Sent: zondag 1 augustus 2010 14:04
 To: sam-users@nvg.ntnu.no
 Subject: RE: Dizzy (was:Porting spectrum games...)

 This will be a nightmare to get into z80 ;)  that is the downside. (unless
 you build it using Sam C - it might compile under that) but i think a z80
 version would be required.

 -Original Message-
 From: owner-sam-us...@nvg.ntnu.no [mailto:owner-sam-us...@nvg.ntnu.no] On
 Behalf Of Thomas Harte
 Sent: 01 August 2010 12:16
 To: sam-users@nvg.ntnu.no
 Subject: Re: Dizzy (was:Porting spectrum games...)

 As a quick mea culpa, there was a bug in my code that means the second
 set of figures I had were wrong. I'm back to an average 10% and up to
 15% worse than Adrian.

 On Sun, Aug 1, 2010 at 9:37 AM, Frode Tennebø fr...@tennebo.com wrote:
 On Sun, 01 Aug 2010 10:18:55 +0200, Andrew Park alp...@ntlworld.com
 wrote:

 Back in the days of the Sam there was a screen compressing utility which
 was ok, anyone know where i can find it?

 Lord Insanity's Screen Cruncher

 (ftp://ftp.nvg.ntnu.no/pub/sam-coupe/disks/utils/LordInsanityScreenCruncher.
 zip)?

  -Frode

 --
 ^ Frode Tennebø | email: fr...@tennebo.com | fr...@irc ^
 |  with Standard.Disclaimer; use Standard.Disclaimer;  |





 No virus found in this incoming message.
 Checked by AVG - www.avg.com
 Version: 9.0.851 / Virus Database: 271.1.1/3042 - Release Date: 07/31/10
 20:34:00

Re: Dizzy (was:Porting spectrum games...)

[Thomas Harte]

As a quick mea culpa, there was a bug in my code that means the second
set of figures I had were wrong. I'm back to an average 10% and up to
15% worse than Adrian.

On Sun, Aug 1, 2010 at 9:37 AM, Frode Tennebø fr...@tennebo.com wrote:
 On Sun, 01 Aug 2010 10:18:55 +0200, Andrew Park alp...@ntlworld.com wrote:

 Back in the days of the Sam there was a screen compressing utility which
 was ok, anyone know where i can find it?

 Lord Insanity's Screen Cruncher
 (ftp://ftp.nvg.ntnu.no/pub/sam-coupe/disks/utils/LordInsanityScreenCruncher.zip)?

  -Frode

 --
 ^ Frode Tennebø | email: fr...@tennebo.com | fr...@irc ^
 |  with Standard.Disclaimer; use Standard.Disclaimer;  |

Re: Dizzy (was:Porting spectrum games...)

[Thomas Harte]

Sadly I'm already doing that and still doing a lot worse than you. At
this point I'd definitely suggest that if you're willing to donate
code then it be used over anything I can come up with.

I'm still trying though!

On Sat, Jul 31, 2010 at 1:23 PM, Adrian Brown
adr...@apbcomputerservices.co.uk wrote:
 Oh one thing ive found out that may help in your tests.  Dont compress
 the data as nibble pairs.  If you convert the data into bytes (only
 using values 0 - 15) then compress that.  (obviously in the decompressor
 you need to patch it back so two bytes become one nibble). You may find
 you get a much better compression rate.

 Adrian

 -Original Message-
 From: owner-sam-us...@nvg.ntnu.no [mailto:owner-sam-us...@nvg.ntnu.no]
 On Behalf Of Adrian Brown
 Sent: 31 July 2010 13:16
 To: sam-users@nvg.ntnu.no
 Subject: RE: Dizzy (was:Porting spectrum games...)

 Ok, providing I havent made any mistakes on the compressor it looks like
 the sizes are down at:

 1: 256 x 141 : 4416
 2: 256 x 141 : 5613
 3: 256 x 192 : 9103
 4: 256 x 192 : 8594
 5: 256 x 192 : 10103

 Ill write the decompressor and check, depends how slow it is to
 decompress i guess ;)

Re: Dizzy (was:Porting spectrum games...)

[Thomas Harte]

Oh, but for the record, with what I think is a completely straight
reimplementation of PNG that isn't particularly intelligent in
searching for the smallest size:

1: 256 x 141 : 5190 (774 bytes worse than you)
2: 256 x 141 : 6439  (826 bytes worse)
3: 256 x 192 : 10041 (938 bytes worse)
4: 256 x 192 : 9326 (732 bytes worse)
5: 256 x 192 : 10599 (496 bytes worse)

Which puts me, on average, about 10% worse than you.

On Sat, Jul 31, 2010 at 1:33 PM, Thomas Harte tomh.retros...@gmail.com wrote:
 Sadly I'm already doing that and still doing a lot worse than you. At
 this point I'd definitely suggest that if you're willing to donate
 code then it be used over anything I can come up with.

 I'm still trying though!

 On Sat, Jul 31, 2010 at 1:23 PM, Adrian Brown
 adr...@apbcomputerservices.co.uk wrote:
 Oh one thing ive found out that may help in your tests.  Dont compress
 the data as nibble pairs.  If you convert the data into bytes (only
 using values 0 - 15) then compress that.  (obviously in the decompressor
 you need to patch it back so two bytes become one nibble). You may find
 you get a much better compression rate.

 Adrian

 -Original Message-
 From: owner-sam-us...@nvg.ntnu.no [mailto:owner-sam-us...@nvg.ntnu.no]
 On Behalf Of Adrian Brown
 Sent: 31 July 2010 13:16
 To: sam-users@nvg.ntnu.no
 Subject: RE: Dizzy (was:Porting spectrum games...)

 Ok, providing I havent made any mistakes on the compressor it looks like
 the sizes are down at:

 1: 256 x 141 : 4416
 2: 256 x 141 : 5613
 3: 256 x 192 : 9103
 4: 256 x 192 : 8594
 5: 256 x 192 : 10103

 Ill write the decompressor and check, depends how slow it is to
 decompress i guess ;)

Re: Dizzy (was:Porting spectrum games...)

[Thomas Harte]

Oh, but wait! Enabling searching for the best LZ77 window and pattern
size (just in terms of 4 bits, 8 bits, 12 bits or 16 bits — not a
completely free search) seems to put me at:

1: 256 x 141 : 4593
2: 256 x 141 : 5731
3: 256 x 192 : 8520
4: 256 x 192 : 8267
5: 256 x 192 : 9440

Currently a little worse than you for the Dizzys, a little better for
the Flashbacks. I'm going to see if there's anything to gain from
variable length LZ77 regions (at the minute it picks the predictor per
line by trying every predictor with every combination of LZ77 length,
then bundles together all the best predictors into a big block and
LZ77s the whole lot, finding the best window/pattern size afresh for
the whole lot). I guess I can look for patterns in the results of the
line-by-line search.

On Sat, Jul 31, 2010 at 2:04 PM, Thomas Harte tomh.retros...@gmail.com wrote:
 Oh, but for the record, with what I think is a completely straight
 reimplementation of PNG that isn't particularly intelligent in
 searching for the smallest size:

 1: 256 x 141 : 5190 (774 bytes worse than you)
 2: 256 x 141 : 6439  (826 bytes worse)
 3: 256 x 192 : 10041 (938 bytes worse)
 4: 256 x 192 : 9326 (732 bytes worse)
 5: 256 x 192 : 10599 (496 bytes worse)

 Which puts me, on average, about 10% worse than you.

 On Sat, Jul 31, 2010 at 1:33 PM, Thomas Harte tomh.retros...@gmail.com 
 wrote:
 Sadly I'm already doing that and still doing a lot worse than you. At
 this point I'd definitely suggest that if you're willing to donate
 code then it be used over anything I can come up with.

 I'm still trying though!

 On Sat, Jul 31, 2010 at 1:23 PM, Adrian Brown
 adr...@apbcomputerservices.co.uk wrote:
 Oh one thing ive found out that may help in your tests.  Dont compress
 the data as nibble pairs.  If you convert the data into bytes (only
 using values 0 - 15) then compress that.  (obviously in the decompressor
 you need to patch it back so two bytes become one nibble). You may find
 you get a much better compression rate.

 Adrian

 -Original Message-
 From: owner-sam-us...@nvg.ntnu.no [mailto:owner-sam-us...@nvg.ntnu.no]
 On Behalf Of Adrian Brown
 Sent: 31 July 2010 13:16
 To: sam-users@nvg.ntnu.no
 Subject: RE: Dizzy (was:Porting spectrum games...)

 Ok, providing I havent made any mistakes on the compressor it looks like
 the sizes are down at:

 1: 256 x 141 : 4416
 2: 256 x 141 : 5613
 3: 256 x 192 : 9103
 4: 256 x 192 : 8594
 5: 256 x 192 : 10103

 Ill write the decompressor and check, depends how slow it is to
 decompress i guess ;)

Re: Dizzy (was:Porting spectrum games...)

[Thomas Harte]

Could it be the simple fact that I'm sorting the palette by hue to try
to make the numeric predictor more likely to be helpful? Ordering
obviously makes a difference, but there isn't time to try all of the
16! possibilities so that's my current guess. Another way through
might be to build some sort of graph that awards each palette colour a
distance from the other colours depending on the probability of it
falling next to them in the image, then to arrange the palette so that
colours that are more likely to be nearby in the image are more likely
to be nearby in the palette.

On Sat, Jul 31, 2010 at 3:01 PM, Adrian Brown
adr...@apbcomputerservices.co.uk wrote:
 Yer - yours is probably a little better then, the flashback screens are more 
 what you want to look at.  Ill play around a little more.

 Adrian

 -Original Message-
 From: owner-sam-us...@nvg.ntnu.no [mailto:owner-sam-us...@nvg.ntnu.no] On 
 Behalf Of Thomas Harte
 Sent: 31 July 2010 14:31
 To: sam-users@nvg.ntnu.no
 Subject: Re: Dizzy (was:Porting spectrum games...)

 Oh, but wait! Enabling searching for the best LZ77 window and pattern
 size (just in terms of 4 bits, 8 bits, 12 bits or 16 bits - not a
 completely free search) seems to put me at:

 1: 256 x 141 : 4593
 2: 256 x 141 : 5731
 3: 256 x 192 : 8520
 4: 256 x 192 : 8267
 5: 256 x 192 : 9440

 Currently a little worse than you for the Dizzys, a little better for
 the Flashbacks. I'm going to see if there's anything to gain from
 variable length LZ77 regions (at the minute it picks the predictor per
 line by trying every predictor with every combination of LZ77 length,
 then bundles together all the best predictors into a big block and
 LZ77s the whole lot, finding the best window/pattern size afresh for
 the whole lot). I guess I can look for patterns in the results of the
 line-by-line search.

 On Sat, Jul 31, 2010 at 2:04 PM, Thomas Harte tomh.retros...@gmail.com 
 wrote:
 Oh, but for the record, with what I think is a completely straight
 reimplementation of PNG that isn't particularly intelligent in
 searching for the smallest size:

 1: 256 x 141 : 5190 (774 bytes worse than you)
 2: 256 x 141 : 6439  (826 bytes worse)
 3: 256 x 192 : 10041 (938 bytes worse)
 4: 256 x 192 : 9326 (732 bytes worse)
 5: 256 x 192 : 10599 (496 bytes worse)

 Which puts me, on average, about 10% worse than you.

 On Sat, Jul 31, 2010 at 1:33 PM, Thomas Harte tomh.retros...@gmail.com 
 wrote:
 Sadly I'm already doing that and still doing a lot worse than you. At
 this point I'd definitely suggest that if you're willing to donate
 code then it be used over anything I can come up with.

 I'm still trying though!

 On Sat, Jul 31, 2010 at 1:23 PM, Adrian Brown
 adr...@apbcomputerservices.co.uk wrote:
 Oh one thing ive found out that may help in your tests.  Dont compress
 the data as nibble pairs.  If you convert the data into bytes (only
 using values 0 - 15) then compress that.  (obviously in the decompressor
 you need to patch it back so two bytes become one nibble). You may find
 you get a much better compression rate.

 Adrian

 -Original Message-
 From: owner-sam-us...@nvg.ntnu.no [mailto:owner-sam-us...@nvg.ntnu.no]
 On Behalf Of Adrian Brown
 Sent: 31 July 2010 13:16
 To: sam-users@nvg.ntnu.no
 Subject: RE: Dizzy (was:Porting spectrum games...)

 Ok, providing I havent made any mistakes on the compressor it looks like
 the sizes are down at:

 1: 256 x 141 : 4416
 2: 256 x 141 : 5613
 3: 256 x 192 : 9103
 4: 256 x 192 : 8594
 5: 256 x 192 : 10103

 Ill write the decompressor and check, depends how slow it is to
 decompress i guess ;)

Re: Dizzy (was:Porting spectrum games...)

[Thomas Harte]

They're 16 colour (quite poorly in one case), but not necessarily
using colours actually available on the Sam's. I've appended the
correct number of bits to store a Sam palette after the compressed
region.

I've also discovered a bug that makes all my numbers worse. I'm
tapping this on the bus so can't give you actual numbers but it's of
the order of 6.something kb for the first and 7 or 8 for the second.
I'm hoping to be able to shrink again, as right now I'm doing no
better than standard deflate, I think.

On Friday, July 30, 2010, Adrian Brown adr...@apbcomputerservices.co.uk wrote:
 Thanks, ill have a quick go.  The only thing wil be PNG is a very good format 
 for compression.  Are these colour reduced to sam already or not?

 Adrian

 -Original Message-
 From: owner-sam-us...@nvg.ntnu.no [mailto:owner-sam-us...@nvg.ntnu.no] On 
 Behalf Of Thomas Harte
 Sent: 29 July 2010 19:31
 To: sam-users@nvg.ntnu.no
 Subject: Re: Dizzy (was: Porting spectrum games...)

 Oh, but I haven't actually tested the output stream yet. So for all I
 know, some error is lurking somewhere making my numbers smaller by
 accidentally throwing data away...

 On Thu, Jul 29, 2010 at 7:00 PM, Thomas Harte tomh.retros...@gmail.com 
 wrote:
 I'll wager you can do better at compression than I can at present, as
 I'm almost completely new to this. But that makes it interesting.

 It's obviously wrong to focus too heavily on any test set, but I've
 bundled together the five images I'm currently testing with, in their
 optimal PNG forms, and uploaded to
 http://members.allegro.cc/ThomasHarte/temp/SamTestScreens.zip

 You should get files screen1 to screen5 (two from Dizzy, three from
 Flashback) which as PNGs are sized 5,553, 6,108, 10,643, 10,005 and
 11,533 bytes respectively.

 The only thing implicit in my output data is that the images are 256
 pixels wide. Not all are 192 pixels high but the height is left
 implicit from the total number of pixels. Palettes are included with
 the images.

 With that in mind, I'm currently at 5,531, 7,273, 11,956, 10,538 and
 12,367 bytes. But still working on it. So I won't take offence if you
 embarrass me thoroughly...

 On Thu, Jul 29, 2010 at 4:18 PM, Adrian Brown
 adr...@apbcomputerservices.co.uk wrote:
 I hope these will support the EEPROM highscore saving or similar ;).  Ive 
 got some strange compression modes, bung me the image and ill see how well 
 i can compress it.  Good to see people looking at the Sam again.  Im hoping 
 to get some more time on Sam Uip soon

 Adrian

 -Original Message-
 From: owner-sam-us...@nvg.ntnu.no [mailto:owner-sam-us...@nvg.ntnu.no] On 
 Behalf Of Thomas Harte
 Sent: 28 July 2010 22:31
 To: sam-users@nvg.ntnu.no
 Subject: Re: Dizzy (was: Porting spectrum games...)

 Hmmm, not doing very well with the Flashback image I chose to test
 (the top left screen) at all. PNG is 10,649 bytes and I'm 13,507
 bytes. But unlike yesterday, that's with the Huffman tree stored
 (whoops!) and the palette thrown on. I've also tweaked the LZ77 stage
 a bit, so it's now a 256 pixel rolling buffer with repetitions up to
 18 pixels in length and the entire screen compressed as one block.

 That said, at one point the storage space for all three images seemed
 to go up by about 1.5kb for absolutely no reason. So I don't
 thoroughly trust my code.

 I've tried sorting the palette by hue (to give it some sort of
 likelihood that nearby colours are near each other in the palette) and
 applying the various PNG prediction filters to the entire image with
 each and every one causing the file size to grow. Which is quiet
 probably why PNG picks them line by line. So that's the experiment for
 tomorrow night...

 On Wed, Jul 28, 2010 at 10:53 AM, Thomas Harte tomh.retros...@gmail.com 
 wrote:
 The previously posted Fantasy World Dizzy map seems to have come from
 'Hall of Light', which offers itself as 'the database of Amiga games'
 at http://hol.abime.net/. You can't just chop up the map and reuse it
 though, as they've watermarked it with an alpha transparency. It's
 large but quite spaced out, so I've just used screens that the
 watermark doesn't touch. And probably if you had a piece of software
 that was at all competent at reducing colour depth then you'd be able
 to wash it off again.

 On Wed, Jul 28, 2010 at 10:03 AM, Stefan Drissen
 stefan.dris...@gmail.com wrote:
 For Amiga Treasure Island Dizzy:

 http://www.vgmaps.com/Atlas/Amiga/TreasureIslandDizzy-Trea

Re: Dizzy (was:Porting spectrum games...)

[Thomas Harte]

It looks better and it means that the off-the-shelf tools for creating
screens are substantially more advanced, being things like Photoshop,
and the skills for creating them are much more widespread. If people
are willing to help, they just need to use whatever they normally use.

Even at gzip level compression you're probably safe to get the 60
screens of Fantasy World Dizzy onto a disk, so going multiload is a
sufficient safety net. Cartoon-style graphics generally compress quite
well in any case, so it's not unrealistic to hope that the 60 screens
can be stored simultaneously in 512 kb along with the rest of the
program. PNG then came into it as evidence of how compact you can make
graphics using well-documented algorithms.

That I happen to be using screenshots grabbed from tile-based games
for testing is just because 16 colour games were often tile based and
reducing colour on higher colour screenshots tends to lead to large
areas of solid colour that may not be a realistic test. I have also
been testing downsampled screens from things like Day of the Tentacle,
getting size reductions still in the 40+% range but the tool I have
for palette reductions is really rather useless so I'm not putting any
substantial weight on that.

On Fri, Jul 30, 2010 at 11:20 AM, Adrian Brown
adr...@apbcomputerservices.co.uk wrote:
 Cant remember, was there a reason for individual png and not tile systems 
 like the originals used.  In Flashback (IIRC) it uses multi layer maps

 Adrian

 -Original Message-
 From: owner-sam-us...@nvg.ntnu.no [mailto:owner-sam-us...@nvg.ntnu.no] On 
 Behalf Of Thomas Harte
 Sent: 30 July 2010 11:15
 To: sam-users@nvg.ntnu.no
 Subject: Re: Dizzy (was:Porting spectrum games...)

 They're 16 colour (quite poorly in one case), but not necessarily
 using colours actually available on the Sam's. I've appended the
 correct number of bits to store a Sam palette after the compressed
 region.

 I've also discovered a bug that makes all my numbers worse. I'm
 tapping this on the bus so can't give you actual numbers but it's of
 the order of 6.something kb for the first and 7 or 8 for the second.
 I'm hoping to be able to shrink again, as right now I'm doing no
 better than standard deflate, I think.

 On Friday, July 30, 2010, Adrian Brown adr...@apbcomputerservices.co.uk 
 wrote:
 Thanks, ill have a quick go.  The only thing wil be PNG is a very good 
 format for compression.  Are these colour reduced to sam already or not?

 Adrian

 -Original Message-
 From: owner-sam-us...@nvg.ntnu.no [mailto:owner-sam-us...@nvg.ntnu.no] On 
 Behalf Of Thomas Harte
 Sent: 29 July 2010 19:31
 To: sam-users@nvg.ntnu.no
 Subject: Re: Dizzy (was: Porting spectrum games...)

 Oh, but I haven't actually tested the output stream yet. So for all I
 know, some error is lurking somewhere making my numbers smaller by
 accidentally throwing data away...

 On Thu, Jul 29, 2010 at 7:00 PM, Thomas Harte tomh.retros...@gmail.com 
 wrote:
 I'll wager you can do better at compression than I can at present, as
 I'm almost completely new to this. But that makes it interesting.

 It's obviously wrong to focus too heavily on any test set, but I've
 bundled together the five images I'm currently testing with, in their
 optimal PNG forms, and uploaded to
 http://members.allegro.cc/ThomasHarte/temp/SamTestScreens.zip

 You should get files screen1 to screen5 (two from Dizzy, three from
 Flashback) which as PNGs are sized 5,553, 6,108, 10,643, 10,005 and
 11,533 bytes respectively.

 The only thing implicit in my output data is that the images are 256
 pixels wide. Not all are 192 pixels high but the height is left
 implicit from the total number of pixels. Palettes are included with
 the images.

 With that in mind, I'm currently at 5,531, 7,273, 11,956, 10,538 and
 12,367 bytes. But still working on it. So I won't take offence if you
 embarrass me thoroughly...

 On Thu, Jul 29, 2010 at 4:18 PM, Adrian Brown
 adr...@apbcomputerservices.co.uk wrote:
 I hope these will support the EEPROM highscore saving or similar ;).  Ive 
 got some strange compression modes, bung me the image and ill see how well 
 i can compress it.  Good to see people looking at the Sam again.  Im 
 hoping to get some more time on Sam Uip soon

 Adrian

 -Original Message-
 From: owner-sam-us...@nvg.ntnu.no [mailto:owner-sam-us...@nvg.ntnu.no] On 
 Behalf Of Thomas Harte
 Sent: 28 July 2010 22:31
 To: sam-users@nvg.ntnu.no
 Subject: Re: Dizzy (was: Porting spectrum games...)

 Hmmm, not doing very well with the Flashback image I chose to test
 (the top left screen) at all. PNG is 10,649 bytes and I'm 13,507
 bytes. But unlike yesterday, that's with the Huffman tree stored
 (whoops!) and the palette thrown on. I've also tweaked the LZ77 stage
 a bit, so it's now a 256 pixel rolling buffer with repetitions up to
 18 pixels in length and the entire screen compressed as one block.

 That said, at one point the storage space for all three images

Re: Dizzy (was: Porting spectrum games...)

[Thomas Harte]

I'll wager you can do better at compression than I can at present, as
I'm almost completely new to this. But that makes it interesting.

It's obviously wrong to focus too heavily on any test set, but I've
bundled together the five images I'm currently testing with, in their
optimal PNG forms, and uploaded to
http://members.allegro.cc/ThomasHarte/temp/SamTestScreens.zip

You should get files screen1 to screen5 (two from Dizzy, three from
Flashback) which as PNGs are sized 5,553, 6,108, 10,643, 10,005 and
11,533 bytes respectively.

The only thing implicit in my output data is that the images are 256
pixels wide. Not all are 192 pixels high but the height is left
implicit from the total number of pixels. Palettes are included with
the images.

With that in mind, I'm currently at 5,531, 7,273, 11,956, 10,538 and
12,367 bytes. But still working on it. So I won't take offence if you
embarrass me thoroughly...

On Thu, Jul 29, 2010 at 4:18 PM, Adrian Brown
adr...@apbcomputerservices.co.uk wrote:
 I hope these will support the EEPROM highscore saving or similar ;).  Ive got 
 some strange compression modes, bung me the image and ill see how well i can 
 compress it.  Good to see people looking at the Sam again.  Im hoping to get 
 some more time on Sam Uip soon

 Adrian

 -Original Message-
 From: owner-sam-us...@nvg.ntnu.no [mailto:owner-sam-us...@nvg.ntnu.no] On 
 Behalf Of Thomas Harte
 Sent: 28 July 2010 22:31
 To: sam-users@nvg.ntnu.no
 Subject: Re: Dizzy (was: Porting spectrum games...)

 Hmmm, not doing very well with the Flashback image I chose to test
 (the top left screen) at all. PNG is 10,649 bytes and I'm 13,507
 bytes. But unlike yesterday, that's with the Huffman tree stored
 (whoops!) and the palette thrown on. I've also tweaked the LZ77 stage
 a bit, so it's now a 256 pixel rolling buffer with repetitions up to
 18 pixels in length and the entire screen compressed as one block.

 That said, at one point the storage space for all three images seemed
 to go up by about 1.5kb for absolutely no reason. So I don't
 thoroughly trust my code.

 I've tried sorting the palette by hue (to give it some sort of
 likelihood that nearby colours are near each other in the palette) and
 applying the various PNG prediction filters to the entire image with
 each and every one causing the file size to grow. Which is quiet
 probably why PNG picks them line by line. So that's the experiment for
 tomorrow night...

 On Wed, Jul 28, 2010 at 10:53 AM, Thomas Harte tomh.retros...@gmail.com 
 wrote:
 The previously posted Fantasy World Dizzy map seems to have come from
 'Hall of Light', which offers itself as 'the database of Amiga games'
 at http://hol.abime.net/. You can't just chop up the map and reuse it
 though, as they've watermarked it with an alpha transparency. It's
 large but quite spaced out, so I've just used screens that the
 watermark doesn't touch. And probably if you had a piece of software
 that was at all competent at reducing colour depth then you'd be able
 to wash it off again.

 On Wed, Jul 28, 2010 at 10:03 AM, Stefan Drissen
 stefan.dris...@gmail.com wrote:
 For Amiga Treasure Island Dizzy:

 http://www.vgmaps.com/Atlas/Amiga/TreasureIslandDizzy-TreasureIsland.png

 The www.vgmaps.com site has quite a few more cool maps (for example the
 Flashback ones in my previous post).


 Stefan


 -Original Message-
 From: owner-sam-us...@nvg.ntnu.no [mailto:owner-sam-us...@nvg.ntnu.no] On
 Behalf Of Andrew Park
 Sent: Wednesday, July 28, 2010 10:29
 To: sam-users@nvg.ntnu.no
 Subject: RE: Dizzy (was: Porting spectrum games...)

 It is great to see some activity on here again, 1 quick question where did
 the amiga dizzy map come from to get screens, i've been looking for good
 amiga screenshot maps everywhere as i'm not an artist and this stops me
 writing games, i like to see graphical progress when i'm writing.

 Anybody send me a link?

 Andy

 -Original Message-
 From: owner-sam-us...@nvg.ntnu.no [mailto:owner-sam-us...@nvg.ntnu.no] On
 Behalf Of Thomas Harte
 Sent: 28 July 2010 00:11
 To: sam-users@nvg.ntnu.no
 Subject: Re: Dizzy (was: Porting spectrum games...)

 Actually, late night spurt - with Huffman trees it's 5,528 bytes and
 6,653 bytes respectively. No predictor yet. The former technically
 beats the PNG size, but I'd imagine that just means the predictor is
 barely going to help and I'm gaining a small win by not including any
 of the normal file padding or headers. Or even the palette.

 On Tue, Jul 27, 2010 at 11:47 PM, Thomas Harte tomh.retros...@gmail.com
 wrote:
 Further to this: I've been playing around with it today using a couple
 of the more complicated screens from that Amiga map which didn't
 feature the watermark (since it's an alpha transparency, causing the
 number of colours to skyrocket), resized to 256 pixels across (which
 makes 141 pixels high). For a sensible lower bound on what I should
 expect, I saved them as PNGs and ran them through OptiPNG

Re: Dizzy (was: Porting spectrum games...)

[Thomas Harte]

Oh, but I haven't actually tested the output stream yet. So for all I
know, some error is lurking somewhere making my numbers smaller by
accidentally throwing data away...

On Thu, Jul 29, 2010 at 7:00 PM, Thomas Harte tomh.retros...@gmail.com wrote:
 I'll wager you can do better at compression than I can at present, as
 I'm almost completely new to this. But that makes it interesting.

 It's obviously wrong to focus too heavily on any test set, but I've
 bundled together the five images I'm currently testing with, in their
 optimal PNG forms, and uploaded to
 http://members.allegro.cc/ThomasHarte/temp/SamTestScreens.zip

 You should get files screen1 to screen5 (two from Dizzy, three from
 Flashback) which as PNGs are sized 5,553, 6,108, 10,643, 10,005 and
 11,533 bytes respectively.

 The only thing implicit in my output data is that the images are 256
 pixels wide. Not all are 192 pixels high but the height is left
 implicit from the total number of pixels. Palettes are included with
 the images.

 With that in mind, I'm currently at 5,531, 7,273, 11,956, 10,538 and
 12,367 bytes. But still working on it. So I won't take offence if you
 embarrass me thoroughly...

 On Thu, Jul 29, 2010 at 4:18 PM, Adrian Brown
 adr...@apbcomputerservices.co.uk wrote:
 I hope these will support the EEPROM highscore saving or similar ;).  Ive 
 got some strange compression modes, bung me the image and ill see how well i 
 can compress it.  Good to see people looking at the Sam again.  Im hoping to 
 get some more time on Sam Uip soon

 Adrian

 -Original Message-
 From: owner-sam-us...@nvg.ntnu.no [mailto:owner-sam-us...@nvg.ntnu.no] On 
 Behalf Of Thomas Harte
 Sent: 28 July 2010 22:31
 To: sam-users@nvg.ntnu.no
 Subject: Re: Dizzy (was: Porting spectrum games...)

 Hmmm, not doing very well with the Flashback image I chose to test
 (the top left screen) at all. PNG is 10,649 bytes and I'm 13,507
 bytes. But unlike yesterday, that's with the Huffman tree stored
 (whoops!) and the palette thrown on. I've also tweaked the LZ77 stage
 a bit, so it's now a 256 pixel rolling buffer with repetitions up to
 18 pixels in length and the entire screen compressed as one block.

 That said, at one point the storage space for all three images seemed
 to go up by about 1.5kb for absolutely no reason. So I don't
 thoroughly trust my code.

 I've tried sorting the palette by hue (to give it some sort of
 likelihood that nearby colours are near each other in the palette) and
 applying the various PNG prediction filters to the entire image with
 each and every one causing the file size to grow. Which is quiet
 probably why PNG picks them line by line. So that's the experiment for
 tomorrow night...

 On Wed, Jul 28, 2010 at 10:53 AM, Thomas Harte tomh.retros...@gmail.com 
 wrote:
 The previously posted Fantasy World Dizzy map seems to have come from
 'Hall of Light', which offers itself as 'the database of Amiga games'
 at http://hol.abime.net/. You can't just chop up the map and reuse it
 though, as they've watermarked it with an alpha transparency. It's
 large but quite spaced out, so I've just used screens that the
 watermark doesn't touch. And probably if you had a piece of software
 that was at all competent at reducing colour depth then you'd be able
 to wash it off again.

 On Wed, Jul 28, 2010 at 10:03 AM, Stefan Drissen
 stefan.dris...@gmail.com wrote:
 For Amiga Treasure Island Dizzy:

 http://www.vgmaps.com/Atlas/Amiga/TreasureIslandDizzy-TreasureIsland.png

 The www.vgmaps.com site has quite a few more cool maps (for example the
 Flashback ones in my previous post).


 Stefan


 -Original Message-
 From: owner-sam-us...@nvg.ntnu.no [mailto:owner-sam-us...@nvg.ntnu.no] On
 Behalf Of Andrew Park
 Sent: Wednesday, July 28, 2010 10:29
 To: sam-users@nvg.ntnu.no
 Subject: RE: Dizzy (was: Porting spectrum games...)

 It is great to see some activity on here again, 1 quick question where did
 the amiga dizzy map come from to get screens, i've been looking for good
 amiga screenshot maps everywhere as i'm not an artist and this stops me
 writing games, i like to see graphical progress when i'm writing.

 Anybody send me a link?

 Andy

 -Original Message-
 From: owner-sam-us...@nvg.ntnu.no [mailto:owner-sam-us...@nvg.ntnu.no] On
 Behalf Of Thomas Harte
 Sent: 28 July 2010 00:11
 To: sam-users@nvg.ntnu.no
 Subject: Re: Dizzy (was: Porting spectrum games...)

 Actually, late night spurt - with Huffman trees it's 5,528 bytes and
 6,653 bytes respectively. No predictor yet. The former technically
 beats the PNG size, but I'd imagine that just means the predictor is
 barely going to help and I'm gaining a small win by not including any
 of the normal file padding or headers. Or even the palette.

 On Tue, Jul 27, 2010 at 11:47 PM, Thomas Harte tomh.retros...@gmail.com
 wrote:
 Further to this: I've been playing around with it today using a couple
 of the more complicated screens from that Amiga map which didn't

Re: Dizzy (was: Porting spectrum games...)

[Thomas Harte]

The previously posted Fantasy World Dizzy map seems to have come from
'Hall of Light', which offers itself as 'the database of Amiga games'
at http://hol.abime.net/. You can't just chop up the map and reuse it
though, as they've watermarked it with an alpha transparency. It's
large but quite spaced out, so I've just used screens that the
watermark doesn't touch. And probably if you had a piece of software
that was at all competent at reducing colour depth then you'd be able
to wash it off again.

On Wed, Jul 28, 2010 at 10:03 AM, Stefan Drissen
stefan.dris...@gmail.com wrote:
 For Amiga Treasure Island Dizzy:

 http://www.vgmaps.com/Atlas/Amiga/TreasureIslandDizzy-TreasureIsland.png

 The www.vgmaps.com site has quite a few more cool maps (for example the
 Flashback ones in my previous post).


 Stefan


 -Original Message-
 From: owner-sam-us...@nvg.ntnu.no [mailto:owner-sam-us...@nvg.ntnu.no] On
 Behalf Of Andrew Park
 Sent: Wednesday, July 28, 2010 10:29
 To: sam-users@nvg.ntnu.no
 Subject: RE: Dizzy (was: Porting spectrum games...)

 It is great to see some activity on here again, 1 quick question where did
 the amiga dizzy map come from to get screens, i've been looking for good
 amiga screenshot maps everywhere as i'm not an artist and this stops me
 writing games, i like to see graphical progress when i'm writing.

 Anybody send me a link?

 Andy

 -Original Message-
 From: owner-sam-us...@nvg.ntnu.no [mailto:owner-sam-us...@nvg.ntnu.no] On
 Behalf Of Thomas Harte
 Sent: 28 July 2010 00:11
 To: sam-users@nvg.ntnu.no
 Subject: Re: Dizzy (was: Porting spectrum games...)

 Actually, late night spurt — with Huffman trees it's 5,528 bytes and
 6,653 bytes respectively. No predictor yet. The former technically
 beats the PNG size, but I'd imagine that just means the predictor is
 barely going to help and I'm gaining a small win by not including any
 of the normal file padding or headers. Or even the palette.

 On Tue, Jul 27, 2010 at 11:47 PM, Thomas Harte tomh.retros...@gmail.com
 wrote:
 Further to this: I've been playing around with it today using a couple
 of the more complicated screens from that Amiga map which didn't
 feature the watermark (since it's an alpha transparency, causing the
 number of colours to skyrocket), resized to 256 pixels across (which
 makes 141 pixels high). For a sensible lower bound on what I should
 expect, I saved them as PNGs and ran them through OptiPNG, PNGCrush,
 and AdvPNG, keeping the smallest version.

 The first (Dylan and a tree) is 5,553 bytes as a PNG. The second
 (featuring the Armorog) 6,108 bytes.

 In my quick dash at compression code, I implemented just a trivial
 little LZ77, using an exhaustive search to pattern match and treating
 each scan line as a completely separate thing to compress (and, as a
 result, rounded up to the next full byte). Five bits for a literal, 17
 for a back reference, the native addressable thing being a nibble.

 From that, I got 6,080 bytes for the first screen and 7,170 for the
 second. And this is without yet implementing a Huffman tree (probably
 best done per screen) or any sort of predictor.

 So, it looks like on a 16 colour display the LZ77 may actually be the
 most of it. In which case it's going to be hard to support the
 conclusion that PNG is massively better than the various common
 techniques when the Sam was a going concern. A Huffman tree is an easy
 win and something I'll experiment with tomorrow hopefully and a
 predictor is a useful addition even when dealing with hard edged low
 colour graphics because it introduces the second dimension as a going
 concern whereas LZ77 has no concept of that.

 Would it be possible to get a single screen hand prepared to be really
 beautiful rather than ripped from a tilemap?

 On Tue, Jul 27, 2010 at 10:46 AM, Stefan Drissen
 stefan.dris...@gmail.com wrote:
 Fair enough. You could of course create PNG tiles so that you do not need
 to
 Flash! anything. You could then even also use a 256-colour PNG image as
 map
 editor, the colour determining the tile... ;-)

 Flashback would be very cool - on the PC I don't remember it having
 scrolling. You would however also need to create an animated PNG / MPEG
 player for the animated sequences.

 Lots of fun things to do... :-)

 -Original Message-
 From: owner-sam-us...@nvg.ntnu.no [mailto:owner-sam-us...@nvg.ntnu.no] On
 Behalf Of the_wub !
 Sent: Monday, July 26, 2010 19:21
 To: sam-users@nvg.ntnu.no
 Subject: Re: Dizzy (was: Porting spectrum games...)

 If png's can be used then I think we should do it even if using an
 image of tiles is a bit ironic!  It would allow changes to be made to
 the image in the gimp rather than flash! if nothing else! ;)  If a
 success, I don't dare to dream about scumm but another possible port
 would be Flashback, I can't remember how much if any scrolling is in
 there but something would be possible if pngs could be used as source
 gfx...
 I don't know enough to comment

Re: Dizzy (was: Porting spectrum games...)

[Thomas Harte]

Hmmm, not doing very well with the Flashback image I chose to test
(the top left screen) at all. PNG is 10,649 bytes and I'm 13,507
bytes. But unlike yesterday, that's with the Huffman tree stored
(whoops!) and the palette thrown on. I've also tweaked the LZ77 stage
a bit, so it's now a 256 pixel rolling buffer with repetitions up to
18 pixels in length and the entire screen compressed as one block.

That said, at one point the storage space for all three images seemed
to go up by about 1.5kb for absolutely no reason. So I don't
thoroughly trust my code.

I've tried sorting the palette by hue (to give it some sort of
likelihood that nearby colours are near each other in the palette) and
applying the various PNG prediction filters to the entire image with
each and every one causing the file size to grow. Which is quiet
probably why PNG picks them line by line. So that's the experiment for
tomorrow night...

On Wed, Jul 28, 2010 at 10:53 AM, Thomas Harte tomh.retros...@gmail.com wrote:
 The previously posted Fantasy World Dizzy map seems to have come from
 'Hall of Light', which offers itself as 'the database of Amiga games'
 at http://hol.abime.net/. You can't just chop up the map and reuse it
 though, as they've watermarked it with an alpha transparency. It's
 large but quite spaced out, so I've just used screens that the
 watermark doesn't touch. And probably if you had a piece of software
 that was at all competent at reducing colour depth then you'd be able
 to wash it off again.

 On Wed, Jul 28, 2010 at 10:03 AM, Stefan Drissen
 stefan.dris...@gmail.com wrote:
 For Amiga Treasure Island Dizzy:

 http://www.vgmaps.com/Atlas/Amiga/TreasureIslandDizzy-TreasureIsland.png

 The www.vgmaps.com site has quite a few more cool maps (for example the
 Flashback ones in my previous post).


 Stefan


 -Original Message-
 From: owner-sam-us...@nvg.ntnu.no [mailto:owner-sam-us...@nvg.ntnu.no] On
 Behalf Of Andrew Park
 Sent: Wednesday, July 28, 2010 10:29
 To: sam-users@nvg.ntnu.no
 Subject: RE: Dizzy (was: Porting spectrum games...)

 It is great to see some activity on here again, 1 quick question where did
 the amiga dizzy map come from to get screens, i've been looking for good
 amiga screenshot maps everywhere as i'm not an artist and this stops me
 writing games, i like to see graphical progress when i'm writing.

 Anybody send me a link?

 Andy

 -Original Message-
 From: owner-sam-us...@nvg.ntnu.no [mailto:owner-sam-us...@nvg.ntnu.no] On
 Behalf Of Thomas Harte
 Sent: 28 July 2010 00:11
 To: sam-users@nvg.ntnu.no
 Subject: Re: Dizzy (was: Porting spectrum games...)

 Actually, late night spurt — with Huffman trees it's 5,528 bytes and
 6,653 bytes respectively. No predictor yet. The former technically
 beats the PNG size, but I'd imagine that just means the predictor is
 barely going to help and I'm gaining a small win by not including any
 of the normal file padding or headers. Or even the palette.

 On Tue, Jul 27, 2010 at 11:47 PM, Thomas Harte tomh.retros...@gmail.com
 wrote:
 Further to this: I've been playing around with it today using a couple
 of the more complicated screens from that Amiga map which didn't
 feature the watermark (since it's an alpha transparency, causing the
 number of colours to skyrocket), resized to 256 pixels across (which
 makes 141 pixels high). For a sensible lower bound on what I should
 expect, I saved them as PNGs and ran them through OptiPNG, PNGCrush,
 and AdvPNG, keeping the smallest version.

 The first (Dylan and a tree) is 5,553 bytes as a PNG. The second
 (featuring the Armorog) 6,108 bytes.

 In my quick dash at compression code, I implemented just a trivial
 little LZ77, using an exhaustive search to pattern match and treating
 each scan line as a completely separate thing to compress (and, as a
 result, rounded up to the next full byte). Five bits for a literal, 17
 for a back reference, the native addressable thing being a nibble.

 From that, I got 6,080 bytes for the first screen and 7,170 for the
 second. And this is without yet implementing a Huffman tree (probably
 best done per screen) or any sort of predictor.

 So, it looks like on a 16 colour display the LZ77 may actually be the
 most of it. In which case it's going to be hard to support the
 conclusion that PNG is massively better than the various common
 techniques when the Sam was a going concern. A Huffman tree is an easy
 win and something I'll experiment with tomorrow hopefully and a
 predictor is a useful addition even when dealing with hard edged low
 colour graphics because it introduces the second dimension as a going
 concern whereas LZ77 has no concept of that.

 Would it be possible to get a single screen hand prepared to be really
 beautiful rather than ripped from a tilemap?

 On Tue, Jul 27, 2010 at 10:46 AM, Stefan Drissen
 stefan.dris...@gmail.com wrote:
 Fair enough. You could of course create PNG tiles so that you do not need
 to
 Flash! anything. You could

Re: Dizzy (was: Porting spectrum games...)

[Thomas Harte]

Further to this: I've been playing around with it today using a couple
of the more complicated screens from that Amiga map which didn't
feature the watermark (since it's an alpha transparency, causing the
number of colours to skyrocket), resized to 256 pixels across (which
makes 141 pixels high). For a sensible lower bound on what I should
expect, I saved them as PNGs and ran them through OptiPNG, PNGCrush,
and AdvPNG, keeping the smallest version.

The first (Dylan and a tree) is 5,553 bytes as a PNG. The second
(featuring the Armorog) 6,108 bytes.

In my quick dash at compression code, I implemented just a trivial
little LZ77, using an exhaustive search to pattern match and treating
each scan line as a completely separate thing to compress (and, as a
result, rounded up to the next full byte). Five bits for a literal, 17
for a back reference, the native addressable thing being a nibble.

From that, I got 6,080 bytes for the first screen and 7,170 for the
second. And this is without yet implementing a Huffman tree (probably
best done per screen) or any sort of predictor.

So, it looks like on a 16 colour display the LZ77 may actually be the
most of it. In which case it's going to be hard to support the
conclusion that PNG is massively better than the various common
techniques when the Sam was a going concern. A Huffman tree is an easy
win and something I'll experiment with tomorrow hopefully and a
predictor is a useful addition even when dealing with hard edged low
colour graphics because it introduces the second dimension as a going
concern whereas LZ77 has no concept of that.

Would it be possible to get a single screen hand prepared to be really
beautiful rather than ripped from a tilemap?

On Tue, Jul 27, 2010 at 10:46 AM, Stefan Drissen
stefan.dris...@gmail.com wrote:
 Fair enough. You could of course create PNG tiles so that you do not need to
 Flash! anything. You could then even also use a 256-colour PNG image as map
 editor, the colour determining the tile... ;-)

 Flashback would be very cool - on the PC I don't remember it having
 scrolling. You would however also need to create an animated PNG / MPEG
 player for the animated sequences.

 Lots of fun things to do... :-)

 -Original Message-
 From: owner-sam-us...@nvg.ntnu.no [mailto:owner-sam-us...@nvg.ntnu.no] On
 Behalf Of the_wub !
 Sent: Monday, July 26, 2010 19:21
 To: sam-users@nvg.ntnu.no
 Subject: Re: Dizzy (was: Porting spectrum games...)

 If png's can be used then I think we should do it even if using an
 image of tiles is a bit ironic!  It would allow changes to be made to
 the image in the gimp rather than flash! if nothing else! ;)  If a
 success, I don't dare to dream about scumm but another possible port
 would be Flashback, I can't remember how much if any scrolling is in
 there but something would be possible if pngs could be used as source
 gfx...
 I don't know enough to comment on the feasibility of it all but I do
 have a question, why use the PC bitmaps and not the ST?  The Atari is
 already 16 colours and it would be easy enough to fancy them up a bit,
 make them a bit less tiley..  I'm saying this without having a good
 look at how the PC gfx would work in 16 colours though...

 Hey Warren!  I'd guess that whichever direction the project goes
 there'll be tons to do.  The more the merrier I say :)

Re: Dizzy (was: Porting spectrum games...)

[Thomas Harte]

Actually, late night spurt — with Huffman trees it's 5,528 bytes and
6,653 bytes respectively. No predictor yet. The former technically
beats the PNG size, but I'd imagine that just means the predictor is
barely going to help and I'm gaining a small win by not including any
of the normal file padding or headers. Or even the palette.

On Tue, Jul 27, 2010 at 11:47 PM, Thomas Harte tomh.retros...@gmail.com wrote:
 Further to this: I've been playing around with it today using a couple
 of the more complicated screens from that Amiga map which didn't
 feature the watermark (since it's an alpha transparency, causing the
 number of colours to skyrocket), resized to 256 pixels across (which
 makes 141 pixels high). For a sensible lower bound on what I should
 expect, I saved them as PNGs and ran them through OptiPNG, PNGCrush,
 and AdvPNG, keeping the smallest version.

 The first (Dylan and a tree) is 5,553 bytes as a PNG. The second
 (featuring the Armorog) 6,108 bytes.

 In my quick dash at compression code, I implemented just a trivial
 little LZ77, using an exhaustive search to pattern match and treating
 each scan line as a completely separate thing to compress (and, as a
 result, rounded up to the next full byte). Five bits for a literal, 17
 for a back reference, the native addressable thing being a nibble.

 From that, I got 6,080 bytes for the first screen and 7,170 for the
 second. And this is without yet implementing a Huffman tree (probably
 best done per screen) or any sort of predictor.

 So, it looks like on a 16 colour display the LZ77 may actually be the
 most of it. In which case it's going to be hard to support the
 conclusion that PNG is massively better than the various common
 techniques when the Sam was a going concern. A Huffman tree is an easy
 win and something I'll experiment with tomorrow hopefully and a
 predictor is a useful addition even when dealing with hard edged low
 colour graphics because it introduces the second dimension as a going
 concern whereas LZ77 has no concept of that.

 Would it be possible to get a single screen hand prepared to be really
 beautiful rather than ripped from a tilemap?

 On Tue, Jul 27, 2010 at 10:46 AM, Stefan Drissen
 stefan.dris...@gmail.com wrote:
 Fair enough. You could of course create PNG tiles so that you do not need to
 Flash! anything. You could then even also use a 256-colour PNG image as map
 editor, the colour determining the tile... ;-)

 Flashback would be very cool - on the PC I don't remember it having
 scrolling. You would however also need to create an animated PNG / MPEG
 player for the animated sequences.

 Lots of fun things to do... :-)

 -Original Message-
 From: owner-sam-us...@nvg.ntnu.no [mailto:owner-sam-us...@nvg.ntnu.no] On
 Behalf Of the_wub !
 Sent: Monday, July 26, 2010 19:21
 To: sam-users@nvg.ntnu.no
 Subject: Re: Dizzy (was: Porting spectrum games...)

 If png's can be used then I think we should do it even if using an
 image of tiles is a bit ironic!  It would allow changes to be made to
 the image in the gimp rather than flash! if nothing else! ;)  If a
 success, I don't dare to dream about scumm but another possible port
 would be Flashback, I can't remember how much if any scrolling is in
 there but something would be possible if pngs could be used as source
 gfx...
 I don't know enough to comment on the feasibility of it all but I do
 have a question, why use the PC bitmaps and not the ST?  The Atari is
 already 16 colours and it would be easy enough to fancy them up a bit,
 make them a bit less tiley..  I'm saying this without having a good
 look at how the PC gfx would work in 16 colours though...

 Hey Warren!  I'd guess that whichever direction the project goes
 there'll be tons to do.  The more the merrier I say :)

Re: Dizzy (was: Porting spectrum games...)

[Thomas Harte]

The gamble is that anything cartoony compresses better than anything
photographic, that PNG is work subsequent to the Sam's heyday,
explaining why we're able to be much more bullish about compression
rates and that if the map stops fitting we can just break it into
multiload. It may not work, but I think it's worth investigating. That
the PC map fits into 250k and the Sam map will have half the bit
depth, less than 80% of the pixels and the memory target is 50% larger
than that is encouraging.

I'm definitely pushing the idea as a way to avoid the look of tiles. I
think that look instantly dates a game.


On 7/26/10, Stefan Drissen stefan.dris...@gmail.com wrote:
 Ummm... whats the point in using a png map if the png is based on tiles?!? I
 thought the idea for using png was to allow some really nice authentic
 graphics to be used that do not look tiley - which the Dizzy map obviously
 does. The png idea could be very good for something NOT tile based (SCUMM
 anyone?)

 I think the repeating tiles are what are allowing these maps to compress so
 well.


 Stefan

 -Original Message-
 From: owner-sam-us...@nvg.ntnu.no [mailto:owner-sam-us...@nvg.ntnu.no] On
 Behalf Of Frode Tennebø
 Sent: maandag 26 juli 2010 08:37
 To: sam-users@nvg.ntnu.no
 Subject: Re: Porting spectrum games...

 On Sun, 25 Jul 2010 23:54:41 +0200, Thomas Harte
 tomh.retros...@gmail.com wrote:

 PNG wasn't a leg pull, though I've been unable to find the Amiga map
 for Fantasy World Dizzy. However, the entire PC map (256 colour,
 individual screens slightly too large) is 250 kb as a PNG. So it'd be
 possible.

 Would this one do:
 http://hol.abime.net/pic_full/gamemap/0501-0600/502_gamemap1.png

 It would take some stiching to make it 100% and fit 256 pixels wide.

 Animated elements are going to need to be repainted frame by
 frame so are logically separate from the background anyway.

 My thought was that animated elements could be tiles in the same way as
 static tiles to save any special handling of those for each screen.
 However, I guess it would be rather straight forward to generalise
 animations as another layer instead?

 -Frode
 --
 ^ Frode Tennebø | email: fr...@tennebo.com | fr...@irc ^
 |  with Standard.Disclaimer; use Standard.Disclaimer;  |

 No virus found in this incoming message.
 Checked by AVG - www.avg.com
 Version: 9.0.851 / Virus Database: 271.1.1/3027 - Release Date: 07/25/10
 08:36:00

Re: Porting spectrum games...

[Thomas Harte]

PNG wasn't a leg pull, though I've been unable to find the Amiga map
for Fantasy World Dizzy. However, the entire PC map (256 colour,
individual screens slightly too large) is 250 kb as a PNG. So it'd be
possible. Animated elements are going to need to be repainted frame by
frame so are logically separate from the background anyway.

I'm unable to get Dizzy.zip (Permission denied), but at this point
it does look more like I'll hold you back rather than help you.

On Sun, Jul 25, 2010 at 9:41 PM, the_wub ! the...@gmail.com wrote:
 I can't take any credit for how things look :)  Not only are they the
 work of someone else but the best of the blit routines are by Chris!

 With animations going on, wouldn't it be impractical not to have a tile
 based system?

 I agree, although if PNG files can be used then the time saved not
 having to make tiles could be spent making special instances for the
 animations..