Re: HP 7970B Capstan?

2017-09-07 Thread Chuck Guzis via cctalk 
On 09/07/2017 07:18 PM, Jon Elson wrote:

> Ah, well, I can see why a 7 track tape won't read well on a 9-track drive!

I was a bit puzzled at why a tapemark would read as 135 (hex).  Sigh--at
least the parity is correct. 

--Chuck

Re: HP 7970B Capstan?

2017-09-07 Thread Jon Elson via cctalk 

On 09/07/2017 02:24 PM, Chuck Guzis via cctalk wrote:

On 09/07/2017 09:32 AM, Al Kossow via cctalk wrote:


The problem you're fighting is things are just a little marginal at 800 ?

As I just mentioned to Al in an offlist email, it turns out that the
stack of tapes labeled "800 NRZ 9 track" are, in fact, 7 track.

Kyread doesn't lie.  Argh.

Time to try out the 7 track stack that Al sent me.


Ah, well, I can see why a 7 track tape won't read well on a 
9-track drive!


Jon

Re: HP 7970B Capstan?

2017-09-07 Thread Chuck Guzis via cctalk 
On 09/07/2017 09:32 AM, Al Kossow via cctalk wrote:

> The problem you're fighting is things are just a little marginal at 800 ?

As I just mentioned to Al in an offlist email, it turns out that the
stack of tapes labeled "800 NRZ 9 track" are, in fact, 7 track.

Kyread doesn't lie.  Argh.

Time to try out the 7 track stack that Al sent me.

--Chuck

4116 DRAM @ VCFMW

2017-09-07 Thread Mike Loewen via cctalk 


   If any VCF Midwest attendees have some spare 4116 dynamic RAM, I could 
use a couple.  Anything 200ns or faster should work.  Please reply 
off-list.  Thanks!



Mike Loewen mloe...@cpumagic.scol.pa.us
Old Technology  http://q7.neurotica.com/Oldtech/

RE: EBAY - DEC RX01/02 floppy disks - Andromeda Systems and AED utilities

2017-09-07 Thread Bill Gunshannon via cctalk 


From: cctalk [cctalk-boun...@classiccmp.org] on behalf of Mark Darvill via 
cctalk [cctalk@classiccmp.org]
Sent: Wednesday, September 6, 2017 11:34 AM
To: N0body H0me; General Discussion: On-Topic and Off-Topic Posts
Subject: Re: EBAY - DEC RX01/02 floppy disks - Andromeda Systems and AED 
utilities

I am in the UK and I have bid for these today and will image them if I win them.

Mark

On 6 Sep 2017, at 15:11, N0body H0me via cctalk  wrote:

>> -Original Message-
>> From: cctalk@classiccmp.org
>> Sent: Wed, 6 Sep 2017 08:37:58 +0200
>> To: cctalk@classiccmp.org
>> Subject: EBAY - DEC RX01/02 floppy disks - Andromeda Systems and AED
>> utilities
>>
>> Someone in the UK is selling a lot of floppy disks (shipping to UK only).
>> Labels mentions "Andromeda Systems WDLT DL/DY Utilities", "WDC11 support
>> disk" and "Advanced Electronic Design WINC-05/8"
>>
>> Unless this type of software isn't already imaged and saved it might be
>> useful if someone in the UK would buy them and image them.
>>
>> http://www.ebay.com/itm/222629853408
>
> For once, an e-bay auction description of RARE is actually warranted
> and accurate.  In my experience, Andromeda Systems material of *ANY*
> stripe is pretty rare-- and there's almost nothing on Bitsavers.
>
> These controllers show up in systems from time to time, but this is
> the first time I've seen the software for them
_

Hmmm...  I have a couple of Andromeda cards here somewhere.
Haven't used them lately as disks are getting real hard to find.  I
do have the documentation (about a dozen typed pages) and I
should have the software here somewhere as well.  But another
copy would be nice in case I can't find mine when I need them.  :-)

I wonder what the chances are some of these third party devices
could be added to SIMH for historical reasons if nothing else.  I know
someone once talked about Terak emulation but I don't know if it
ever got anywhere.

bill

Re: HP 7970B Capstan?

2017-09-07 Thread Jon Elson via cctalk 

On 09/06/2017 10:09 PM, Chuck Guzis via cctalk wrote:
Here's a thought--can skew be adjusted by writing,a block 
of data in a forward direction, then reading it in reverse?
Nope, it will always show perfect skew.  What you COULD do, 
is take the tape off the reel and turn it around.  THEN, any 
skew error would be doubled,  This would be pretty annoying, 
you'd have to write, turn around, check, adjust and then 
repeat with the write step.


Jon

Re: HP 7970B Capstan?

2017-09-07 Thread Al Kossow via cctalk 


On 9/6/17 9:20 PM, Chuck Guzis via cctalk wrote:

> If you could spare it for a week or so, I'd be grateful.  On the other
> hand, my MCU setup for the drive works great--it reads a tape and
> stashes the data as a .TAP file on an SD card.
The problem you're fighting is things are just a little marginal at 800 ?

Re: determing date on TI 99/4 computers.

2017-09-07 Thread Liam Proven via cctalk 
On 7 September 2017 at 04:07, Sam O'nella via cctalk
 wrote:

> I don't know if it was my newb brain/false memory but i thought I saw someone 
> post a ti-99/2 prototype before

It was a thing:

http://www.old-computers.com/museum/computer.asp?c=267

Never made it onto retail sale, though.

-- 
Liam Proven • Profile: https://about.me/liamproven
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Re: Scavenging higher-end models (Was: Re: determing date on TI 99/4 computers.)

2017-09-07 Thread Liam Proven via cctalk 
On 6 September 2017 at 20:46, Tapley, Mark  wrote:
> On Sep 6, 2017, at 10:45 AM, Liam Proven via cctalk  
> wrote:
>
>> It shows what the machine could have been, if TI hadn't crippled it
>> for fear of competing with its higher-end models.
>
> I have heard similar arguments repeatedly, in reference to systems 
> from multiple different companies (DEC in particular, but also IBM, TI as 
> above, etc.).
>
> It seems so short-sighted as to be almost improbable to me. Of 
> *course* if a company can offer similar performance in a cheaper model, they 
> should do that. The high-end customers will still pay premium for the slight 
> extra performance, but the lower-end model will enable a whole cadre of users 
> and developers which would otherwise have been priced away to the competition.
>
> Is this just 20/20 hindsight on my part, or are there factors I don’t 
> understand in this decision? If it’s just internal company politics - 
> high-end system group doesn’t want to get squeezed from below - the CEO’s job 
> is to put a stop to that, I would think.

If there is a general case to be made -- and it's a bit tricky -- then
it's perhaps this:

[1] Make the best system you can for a particular price-point. If
hitting a particular price-point is going to mean horribly
compromising the product, then you probably shouldn't be competing in
that market.

[2] Recognise that home computers are not business computers. What a
home/leisure user wants is not the same as what a professional wants.
Don't attempt to price-gouge the pros, don't attempt to fob home users
off with second-rate rubbish.

[3] If attempting to do both of these means that you have either type
of product stomping all over the other, then you have failed to
properly identify and differentiate your 2 separate markets.

Examples...

The Commodore VIC-20 and the Sinclair ZX-81 were both horribly
compromised, lousily-specified toys, useless for anything serious. But
at the time, that's all a budget home machine could do, and because
the companies' rivals were not offering budget home machines -- they
offered $1000+ pro-level kit -- the machines were huge successes.

Both companies did successor models that were significantly better
(the C64 and ZX Spectrum) and which sold very well.

Then both companies lost the plot a bit and the successor models to
_them_ were both rather poor.

CBM fooled around with incompatible machines that didn't advance the SOTA much.

Sinclair flailed and adapted an uninspiring Spanish model, the
Spectrum 128, which failed to address one of the older model's most
serious failings -- its poor graphics. This is doubly tragic as Timex
_had_ addressed this in the TS2068. If Sinclair had adopted Timex'
improved ULA, the Spectrum 128 would have been a significantly more
competitive machine.

(Another more niche tweak is that the Timex machine could page RAM in
in place of the ROM, enabling it to run CP/M. The Sinclair model
couldn't until years later with the Amstrad designed-and-built
Spectrum +3.)

TI was afraid its home computer would compete with its business
machines, so it crippled it, leaving an uncompetitive product. But the
business machines weren't competitive anyway, and weren't big sellers.

Either it could have just made a more expensive but uncrippled TI99/4A
-- with, say, 32 kB of 16-bit RAM directly attached to the CPU, a
native-code BASIC interpreter instead of 2 different ones, and dumped
the cartridge port and the PEB.

It would have been considerably more expensive than the VIC-20 that it
tried to compete with. The smarter choice would have been to embrace
that and just go with it, IMHO.


-- 
Liam Proven • Profile: https://about.me/liamproven
Email: lpro...@cix.co.uk • Google Mail/Talk/Plus: lpro...@gmail.com
Twitter/Facebook/Flickr: lproven • Skype/LinkedIn/AIM/Yahoo: liamproven
UK: +44 7939-087884 • ČR/WhatsApp/Telegram/Signal: +420 702 829 053