[cctalk] Re: terminology [was: First Personal Computer]

[Tom Hunter via cctalk]

Well said.

On Sun, 26 May 2024, 6:59 pm Liam Proven via cctalk, 
wrote:

> On Sun, 26 May 2024 at 07:50, ben via cctalk 
> wrote:
> >
> > I think the most important thing for a Personal Computer,
> > is the average Joe, can afford and use it.
>
> Yes, agreed.
>
> > The second thing is
> > to have ample memory and IO to run useful programs.
>
> Now, you see, I'd agree with that but then you immediately go and blow
> it out of the water with this:
>
> > The  basic Apple
> > I,II does not count as many others as it had BASIC in ROM and tape IO.
>
> Hang on. So what?
>
> My first computer was a Sinclair ZX Spectrum. 48kB RAM, tape cassette
> storage, floating-point BASIC with graphics commands in ROM. It was an
> ample  amount of RAM, it could run useful programs, and I both bought
> hundreds of them and wrote my own.
>
> What kind of subjective elitist BS is this?!
>
> My Spectrum outspecced many early CP/M machines and they sold in the
> hundreds of thousands to millions (worldwide, amalgamating all brands)
> and spawned a multi-TRILLION-dollar industry, but in the opinion of
> the mighty Mr I-don't-need-a-capital-letter-or-a-surname ben, they
> don't count?
>
> Get in the sea.
>
> Utter tosh. You dismiss an entire decade's worth of hardware that
> created careers, shaped the economies of nations, and arguably caused
> the collapse of communism in Europe because you don't approve?
>
> No. Not for a second, not to be even entertained for amusement for an
> instant, no.
>
>
> > The third thing is a real OS. Nobody has one, as a personal computer.
>
> Tell me you never used DOS in anger, never saw CCP/M and CDOS and QNX
> and DESQview, or Xenix, or really knew the PC platform at all, without
> telling me. Utter bilgewater. Apparently you never even saw Borland
> Sidekick.
>
> Ill-informed nonsense.
>
>
> > CP/M and MSDOS does not handle IRQ's.
>
> Wrong.
>
> > Unix for the PDP-11 is real
> > operating system but not personal as it requires a admin,and a swapping
> > media.
>
> Irrelevant.
>
>
> --
> Liam Proven ~ Profile: https://about.me/liamproven
> Email: lpro...@cix.co.uk ~ gMail/gTalk/FB: lpro...@gmail.com
> Twitter/LinkedIn: lproven ~ Skype: liamproven
> IoM: (+44) 7624 277612: UK: (+44) 7939-087884
> Czech [+ WhatsApp/Telegram/Signal]: (+420) 702-829-053
>

[cctalk] Re: Random items on Pascal #3

[Tom Hunter via cctalk]

I assume you refer to the "case ... of" construct in PASCAL record types
which allowed you to arbitrarily "cast" - to use a C term - variables to
any type you wanted and could be (ab)used to assign integers to pointers.

The ability to call PP programs via RA+1 calls was not a loop hole, but a
design feature of the CYBER/6600 operating systems like COS, KRONOS and
NOS. It simply involved writing to the word in location 1 (RA+1) relative
to the start of the segment of memory assigned to your program by the OS.
The contents of the word were essentially the name of the PP program and
some parameters - typically the address of a parameter block somewhere in
your segment of memory. When the OS processed the request, it cleared
location 1 (RA+1). This was the standard mechanism used to request OS
functions like writing to a file etc. Higher level languages typically
wrapped this in library functions (or macros when programming in assembler
i.e. COMPASS), but if the language allowed negative array offsets and the
ability to determine the address of the array, then it was trivial to
explicitly call PPs via RA+1 calls (even more trivial using COMPASS).

The OS periodically scanned the RA+1 words of each of several programs
currently in memory (i.e. a program assigned to a "control point") and if
the RA+1 contents were non-zero, then the OS allocated a free PP to the
request and loaded and started the requested PP program into that PP and
finally cleared the word at RA+1. You typically would expedite this by
after writing the PP request to RA+1, execute an "exchange jump"
instruction which stopped the user program from running and re-entered the
OS to allow it to soon after process pending RA+1 requests.

I hope this all makes sense.

On Thu, May 16, 2024 at 3:28 PM Mark GREEN via cctalk 
wrote:

>  I worked on the run time support for the early versions of Pascal on the
> CDC 6000 series.  Depending upon the character set determining the end of
> line was a major pain.  There was a loop hole in the Pascal type system
> that allowed you to call any PPU program directly from Pascal.  It was not
> widely known, but it came in handy at times.
> On Thursday, May 16, 2024 at 01:52:12 a.m. EDT, Chuck Guzis via cctalk
>  wrote:
>
>  On 5/15/24 22:07, Tom Hunter via cctalk wrote:
> > I thought the CDC CYBER and 6000 series mainframes were great systems
> which
> > performed admirably for what they were designed for. I liked COMPASS,
> SYMPL
> > and NOS 1 and 2. I didn't do much work in CYBIL, but it was basically an
> > enhanced version of PASCAL suitable for operating systems work. What is
> > there not to like? These mainframes and the CDC 7600 outperformed every
> > other machine until Seymour Cray released his own machines.
>
> SYMPL was pretty new when I left the 6000 series behind.  Much of the
> code, but for some utilities was still assembly.  FORTRAN (FTN) was used
> for some simple things.
> I worked on Zodiac, which was a multi-CPU COBOL  (!) multithreaded
> multitask OS written for USAF--very unlike anything CDC has ever had..
> Lots of ECS and oceans of 844 drives. Special Systems Division was a lot
> of fun back in the day.  Lots of variety before they started cycling
> down work at SVLOPS.  My final years at CDC Sunnyvale were with STAR,
> only to be resurrected in the 1980s with the ETA machines.
>
> I think the ROVER people were among the last people at SVLOPS, but I
> can't recall precisely.
>
> A little factoid is that the 6000 series was very good at running COBOL.
>
> --Chuck
>
>
>
>

[cctalk] Re: Random items on Pascal #3

[Tom Hunter via cctalk]

I thought the CDC CYBER and 6000 series mainframes were great systems which
performed admirably for what they were designed for. I liked COMPASS, SYMPL
and NOS 1 and 2. I didn't do much work in CYBIL, but it was basically an
enhanced version of PASCAL suitable for operating systems work. What is
there not to like? These mainframes and the CDC 7600 outperformed every
other machine until Seymour Cray released his own machines.

On Thu, May 16, 2024 at 11:08 AM Ken Seefried via cctalk <
cctalk@classiccmp.org> wrote:

> I came to it all a bit later.  I do recall the CDC salesthing saying
> something like "oh, you guys have some Unix around here?  Have we got
> something for you!".  And the systems guys brought up NOS/VE on the last
> CDC machines we ever bought.
>
> On Wed, May 15, 2024 at 10:43 PM Chuck Guzis via cctalk <
> cctalk@classiccmp.org> wrote:
>
> > On 5/15/24 18:47, Ken Seefried via cctalk wrote:
> >
> > > Please...I'm trying very hard not to remember them (or NOS...worse,
> > NOS/VE).
> >
> > I left CDC at around the time that SCOPE 3.4 was being renamed NOS BE
> > and KRONOS was becoming NOS.  I remember attending a design meeting for
> > the pager in what was to become NOS/VE.  I asked the presenter if he'd
> > conferred with any of the virtual memory pager talent that CDC had
> > in-house.  Blank stare.  I informed him that the STAR-100 people had
> > lived in that particular hell since about 1969--and that demand paging
> > was not the way to run a shop.  STAR had long-since switched to a
> > working set algorithm.
> >
> > Even that wasn't enough.  If one selected a large (65 KW) page size and
> > set up certain vector instructions so that addresses crossed page
> > boundaries, it was impossible to get the required pages into memory all
> > at once.
> >
> > The system just sat there and thrashed
> >
> > --Chuck
> >
> >
>

[cctalk] Re: oscilloscopes

[Tom Hunter via cctalk]

I too have experimented with OpenGL to simulate phosphor-decay.
I never got to a satisfactory solution. The learning curve for OpenGL is
steep.


On Sun, Apr 7, 2024 at 4:43 PM Lars Brinkhoff via cctalk <
cctalk@classiccmp.org> wrote:

> Phil Budne wrote:
> > I wrote and tuned the code twenty years ago, but haven't looked at
> > whether better results might be possible by wasting the capabilities
> > of current systems (SIMD libaries and/or multiple cores).  I felt like
> > I only was able to give a slim impression, and I've also wondered what
> > could be done with 4K HDR displays: making points round(!) and
> > simulating the "bloom" and intensity of repeatedly or highly
> > intensified spots.
>
> I have done some experiments in this direction.  There are two sample
> pictures here which are supposed to look similar to a P7 CRT.
>
> https://github.com/larsbrinkhoff/crt-simulation
>

[cctalk] Re: typical IC kits on Amazon and elsewhere

[Tom Hunter via cctalk]

Sorry I mistyped. I meant Mouser and Digikey, not Amazon and Digikey.


On Sun, 31 Mar 2024, 11:48 am Tom Hunter,  wrote:

> I am very happy to buy from Amazon and Digikey even if sometimes they are
> a little more expensive. I want them to be around for the long term, so I
> support them as much as possible. Their range is amazing.
>
> On Sun, 31 Mar 2024, 10:53 am Glen Slick via cctalk, <
> cctalk@classiccmp.org> wrote:
>
>> On Sat, Mar 30, 2024 at 5:11 PM Jonathan Chapman via cctalk
>>  wrote:
>> >
>> > > Standard TTL 74XXX is drying up rather quickly. Futurlec still has
>> some
>> > > TTL but 7404s are all gone. Even LS is hard to find.
>> >
>> > Ours comes from Mouser, between two part #s they have over 7,000
>> 74LS04s in DIP packaging in stock. Didn't check ACT, HCT, or ALS. I don't
>> think we've had a 7400 series part that we couldn't just order off Mouser
>> in recent history, and we're usually buying QTY 100.
>> >
>>
>> You can also buy parts direct from TI, for example they currently show
>> around around 3000 SN74LS04N parts in stock.
>>
>> https://www.ti.com/product/SN74LS04/part-details/SN74LS04N
>>
>> The prices for that part match the current Mouser prices of $0.674
>> each, or $0.519 each if you buy at least 4 tubes of 25 parts.
>>
>> I've bought some tubes of 74LS parts direct from TI in the last year.
>>
>

[cctalk] Re: typical IC kits on Amazon and elsewhere

[Tom Hunter via cctalk]

I am very happy to buy from Amazon and Digikey even if sometimes they are a
little more expensive. I want them to be around for the long term, so I
support them as much as possible. Their range is amazing.

On Sun, 31 Mar 2024, 10:53 am Glen Slick via cctalk, 
wrote:

> On Sat, Mar 30, 2024 at 5:11 PM Jonathan Chapman via cctalk
>  wrote:
> >
> > > Standard TTL 74XXX is drying up rather quickly. Futurlec still has some
> > > TTL but 7404s are all gone. Even LS is hard to find.
> >
> > Ours comes from Mouser, between two part #s they have over 7,000 74LS04s
> in DIP packaging in stock. Didn't check ACT, HCT, or ALS. I don't think
> we've had a 7400 series part that we couldn't just order off Mouser in
> recent history, and we're usually buying QTY 100.
> >
>
> You can also buy parts direct from TI, for example they currently show
> around around 3000 SN74LS04N parts in stock.
>
> https://www.ti.com/product/SN74LS04/part-details/SN74LS04N
>
> The prices for that part match the current Mouser prices of $0.674
> each, or $0.519 each if you buy at least 4 tubes of 25 parts.
>
> I've bought some tubes of 74LS parts direct from TI in the last year.
>

[cctalk] Re: RD54 Maxtor XT-2190 w/one long meep

[Tom Hunter via cctalk]

Thanks Rick for clarifying my somewhat ambiguous description of how to
dislodge a stuck voice coil mechanism.

On Sat, 24 Feb 2024, 12:13 pm Rick Bensene via cctalk, <
cctalk@classiccmp.org> wrote:

> Just make sure when you torque the drive as mentioned that you rotate it
> in as close to the same axis of rotation as the platter(s) spin as
> possible, as any other direction of torque could cause the head(s) to
> impact the platter(s) with more energy than desirable, especially if the
> head(s) are positioned over data areas.
>
> Sometimes the actuator will not fully park when the drive is last powered
> off, especially if things are already gummy.  That can leave the heads over
> area of the disk where data or servo information is recorded, potentially
> causing damage that may not be repairable (without opening the sealed
> area), and likely ruining part or all of the data on the drive (if you care
> about what's on it) even if the positioner is "unstuck" by the torque.
>
> I have successfully (at least temporarily) resurrected some old Maxtor
> XT-1140 (ST-506) drives using this "twist" technique.   My experience shows
> that the technique only works a few times and then it quits working.  Thus,
> if you do get the drive running and care about the data that is on it,
> before powering it up, get it connected up to a system that you can use to
> reliably archive the content, because once you power it back down, it may
> get stuck worse than it was before.
>
> I have not tried "cooking" the drive as also mentioned.
>
>
>
>
> -Original Message-
> From: Tom Hunter via cctalk [mailto:cctalk@classiccmp.org]
> Sent: Friday, February 23, 2024 6:25 PM
> To: General Discussion: On-Topic and Off-Topic Posts <
> cctalk@classiccmp.org>
> Cc: Tom Hunter 
> Subject: [cctalk] Re: RD54 Maxtor XT-2190 w/one long meep
>
> It may be that the voice coil positioner is stuck due to some hardened
> grease.
> If that is the case, you could try holding the drive in your hand and
> flick your wrist hard several times to try to dislodge a possibly stuck
> voice coil.
> Alternatively you could flick the drive against something soft like your
> thigh or a rubber mat.
> Finally you could try to gently heat the drive to about 60 degrees C and
> then immediately before cooling connect it up to exercise the now hopefully
> loosened voice coil mechanism.
>
> On Sat, Feb 24, 2024 at 8:15 AM Jacob Ritorto via cctalk <
> cctalk@classiccmp.org> wrote:
>
> > On Fri, 23 Feb 2024 at 19:01, r.stricklin via cctalk <
> > cctalk@classiccmp.org>
> > wrote:
> >
> > > voice coil positioner.
> >
> >
> > Yikes, so that's an "open the lid" situation, bear?  Any "how to"
> > advise / docs / anecdotes out there as I begin searching?
> >
>

[cctalk] Re: RD54 Maxtor XT-2190 w/one long meep

[Tom Hunter via cctalk]

It may be that the voice coil positioner is stuck due to some hardened
grease.
If that is the case, you could try holding the drive in your hand and flick
your wrist hard several times to try to dislodge a possibly stuck voice
coil.
Alternatively you could flick the drive against something soft like your
thigh or a rubber mat.
Finally you could try to gently heat the drive to about 60 degrees C and
then immediately before cooling connect it up to exercise the now hopefully
loosened voice coil mechanism.

On Sat, Feb 24, 2024 at 8:15 AM Jacob Ritorto via cctalk <
cctalk@classiccmp.org> wrote:

> On Fri, 23 Feb 2024 at 19:01, r.stricklin via cctalk <
> cctalk@classiccmp.org>
> wrote:
>
> > voice coil positioner.
>
>
> Yikes, so that's an "open the lid" situation, bear?  Any "how to" advise /
> docs / anecdotes out there as I begin searching?
>

[cctalk] Re: PDP 11/34 or 11/04 front panel question

[Tom Hunter via cctalk]

I just realised that I never followed up on this.

After some research and a few phone calls to manufacturer support lines I
settled on SikaBond SprayFix as the glue.

The glue is advertised as "contains no chlorinated solvents", is "suitable
for indoor use", is based on a "synthetic polymer", is "repositionable for
1-2 minutes" and has a "low odour". Sounded just right for this application.

I first tried the glue on the bottom left of the plastic sheet which is
normally obscured by the cast metal front. Next morning there was no
indication of any paint damage in the sprayed area.

I cleaned the aluminium plate with aceton and the plastic sheet with
ethyl-alcohol. I built a jig out of a timber board with two thin metal rods
inserted as alignment pins matching the alignment holes in the aluminium
plate and plastic sheet.

I then masked the red transparent areas of the plastic sheet with low-tack
masking tape to prevent glue from getting onto them. This keeps them nice
and clean for good visibility of the LEDs and 6 digit 7-segment display.

With the aluminium plate mounted to the jig I applied a thin layer of the
glue and then the same onto the plastic sheet which was laid out on a sheet
of paper.
I then moved the plastic sheet onto a fresh sheet of paper to avoid
contamination of the front side with glue while I removed the protective
masking tape.
Finally I assembled the plastic sheet onto the aluminium plate with the aid
of the alignment pins and immediately pressed the two halves firmly
together.

After a few minutes I removed the now securely glued assembly from the jig,
flipped it over onto another fresh sheet of paper on the edge of a flat
table with the plastic down onto the paper.
I placed some weights onto the top (i.e. the aluminium sheet) to let it dry
and bond for a few more hours.

The front panel has now been re-assembled and is fully functional and
beautiful.   :-)

On Tue, Nov 7, 2023 at 9:33 AM Tom Hunter  wrote:

> The PDP 11/34 and 11/04 front panels (both operator and programmer) use a
> somewhat stiff plastic sheet of 1.0 mm thickness with DEC logo, model
> designation, labels for the keys printed on it, cut-outs for the keypad and
> knob and red transparent sections for LEDs and 6 digit 7-segment display.
>
> I don't know what the industry calls this type of plastic sheet? Is it a
> "decal"???
>
> This plastic sheet is (was) fixed to an anodized aluminium plate (1.6 mm
> thickness) using some type of glue which has deteriorated so that the
> plastic sheet has separated from the aluminium plate.
>
> The glue looks like it has been sprayed on and has a light yellowish-brown
> appearance. The glue readily dissolves in ethyl-alcohol and acetone, but is
> unaffected by water, petrol (gasoline) and dry cleaning fluid (white
> spirits).
>
> I would like to glue the plastic sheet back onto the aluminium plate, but
> worry about damaging the plastic sheet and/or paint by the solvents in
> typical glues.
> Also some glues don't allow any adjustment once you combine the two halves
> of whatever you glue together.
>
> What type of plastic is this plastic sheet likely made of (polycarbonate?)
> and what paint was used? I am asking to determine what solvent based glues
> may attack either the plastic sheet or the painted surfaces.
>
> The dark grey and transparent red paints are applied to the back side of
> the plastic sheet, so they are vulnerable to solvent attack when glueing. I
> tried ethyl-alcohol in one corner which is obscured by the cast metal
> surround and some of the dark gray colour came off with the alcohol and
> gentle rubbing.
>
> Has anyone successfully glued back the plastic sheet to the aluminium
> plate? If yes, what type of glue did you use and how exactly did you do the
> operation?
>
> Any suggestions, advice or tips?
>
> Thanks and best regards
> Tom Hunter
>
>

[cctalk] Re: It's been a while - retirement project

[Tom Hunter via cctalk]

Thank you Dave!

On Sat, Nov 25, 2023, 6:36 PM silcreval via cctalk 
wrote:

> Dave,
>
> Many thanks for making this source available, I'm going to spend some time
> looking through it all.
>
>
>

[cctalk] Re: PDP-8/E front panels

[Tom Hunter via cctalk]

I had some toggles printed for me professionally, but they are inferior to
the originals and the colours don't match.

If anyone has spare DEC LAB-8/e switches please let me know.

Thanks
Tom

On Fri, Nov 17, 2023, 10:14 PM Bill Gunshannon via cctalk <
cctalk@classiccmp.org> wrote:

>
>
> On 11/17/2023 8:52 AM, Tom Hunter via cctalk wrote:
> > Hi Bob,
> > I can't help with your search for 8/e front panels, but you mentioned
> > "green switch boards". I have a nicely restored DEC LAB-8/e with green
> > switch toggles. Do you have spare green switch toggles? I would love to
> > have one dark green and one light green toggle. I don't need the actual
> > switch, but would be happy to take the toggles with switch. Please let me
> > know if you can help.
> >
>
> Have you ever considered making your own?
>
> https://www.thingiverse.com/thing:360853
>
>
> bill
>

[cctalk] Re: PDP-8/E front panels

[Tom Hunter via cctalk]

Hi Bob,
I can't help with your search for 8/e front panels, but you mentioned
"green switch boards". I have a nicely restored DEC LAB-8/e with green
switch toggles. Do you have spare green switch toggles? I would love to
have one dark green and one light green toggle. I don't need the actual
switch, but would be happy to take the toggles with switch. Please let me
know if you can help.

Tanks and best regards
Tom Hunter


On Fri, Nov 17, 2023, 2:18 PM Bob Rosenbloom via cctalk <
cctalk@classiccmp.org> wrote:

> Do you have any more of the DEC PDP-8 e/m/f front panels?
>
> I'm looking for one that matches the layout attached. I don't care what
> model (e/m/f etc.) it's for, but the rotary switch layout needs to be
> right and I prefer the matte finish. Color is not important either I
> have orange, green, and blue switch boards.
>
> Thanks,
>
> Bob
>
> --
> Vintage computers and electronics
> www.dvq.com
> www.tekmuseum.com
> www.decmuseum.org
>

[cctalk] Re: PDP 11/34 or 11/04 front panel question

[Tom Hunter via cctalk]

Thanks for the suggestion Tom.

I have thought about it, but it would have to be a very thin type of tape.
Also very precise positioning of the plastic sheet onto the aluminium plate
is required as once the tape sticks to the other half it won't allow for
repositioning.

Some form of solvent free glue which does not attack the paint would be
better as you can reposition at least for a few seconds.


On Tue, Nov 7, 2023 at 3:33 PM Tom Ivar Helbekkmo via cctalk <
cctalk@classiccmp.org> wrote:

> Tom Hunter via cctalk  writes:
>
> > Any suggestions, advice or tips?
>
> Have you considered simply using double sided tape?
>
> -tih
> --
> Most people who graduate with CS degrees don't understand the significance
> of Lisp.  Lisp is the most important idea in computer science.  --Alan Kay
>

[cctalk] PDP 11/34 or 11/04 front panel question

[Tom Hunter via cctalk]

The PDP 11/34 and 11/04 front panels (both operator and programmer) use a
somewhat stiff plastic sheet of 1.0 mm thickness with DEC logo, model
designation, labels for the keys printed on it, cut-outs for the keypad and
knob and red transparent sections for LEDs and 6 digit 7-segment display.

I don't know what the industry calls this type of plastic sheet? Is it a
"decal"???

This plastic sheet is (was) fixed to an anodized aluminium plate (1.6 mm
thickness) using some type of glue which has deteriorated so that the
plastic sheet has separated from the aluminium plate.

The glue looks like it has been sprayed on and has a light yellowish-brown
appearance. The glue readily dissolves in ethyl-alcohol and acetone, but is
unaffected by water, petrol (gasoline) and dry cleaning fluid (white
spirits).

I would like to glue the plastic sheet back onto the aluminium plate, but
worry about damaging the plastic sheet and/or paint by the solvents in
typical glues.
Also some glues don't allow any adjustment once you combine the two halves
of whatever you glue together.

What type of plastic is this plastic sheet likely made of (polycarbonate?)
and what paint was used? I am asking to determine what solvent based glues
may attack either the plastic sheet or the painted surfaces.

The dark grey and transparent red paints are applied to the back side of
the plastic sheet, so they are vulnerable to solvent attack when glueing. I
tried ethyl-alcohol in one corner which is obscured by the cast metal
surround and some of the dark gray colour came off with the alcohol and
gentle rubbing.

Has anyone successfully glued back the plastic sheet to the aluminium
plate? If yes, what type of glue did you use and how exactly did you do the
operation?

Any suggestions, advice or tips?

Thanks and best regards
Tom Hunter

[cctalk] Re: M7846 RX11 Unibus floppy controller board documentation?

[Tom Hunter via cctalk]

Thank you Christian !!!

Best regards
Tom

On Wed, Oct 18, 2023 at 3:41 PM Christian Corti via cctalk <
cctalk@classiccmp.org> wrote:

> On Wed, 18 Oct 2023, Tom Hunter wrote:
> > I was unable to locate schematics and/or a maintenance manual for the
> > Unibus M7846 RX11 floppy controller board.
>
> On our FTP server ;-)
>
>
> ftp://computermuseum.informatik.uni-stuttgart.de/dec/pdp11/RX11_EngineeringDrawings_13Jun1975.pdf
>
>
> Christian
>

[cctalk] M7846 RX11 Unibus floppy controller board documentation?

[Tom Hunter via cctalk]

I was unable to locate schematics and/or a maintenance manual for the
Unibus M7846 RX11 floppy controller board.

If anyone has these could you please scan them and make them available.

Thank you.
Tom

[cctalk] Re: Theory of operation of DEC H7441 regulator?

[Tom Hunter via cctalk]

Thank you very much Brent !!!

Your explanation beautifully clarified how the H7441 works.
I have asked the same question over at vcfed.org without an answer..
I hope it is Ok to share to vcfed.org what you wrote as others are likely
to struggle too with the complexity of the H7441 in the future and vcfed.org
is searchable.

Thanks again for your time and effort to explain what I really struggled to
understand.

Tom

On Thu, Sep 28, 2023 at 3:29 PM Brent Hilpert via cctalk <
cctalk@classiccmp.org> wrote:

> On 2023-Sep-27, at 9:01 PM, Tom Hunter via cctalk wrote:
> > The DEC H7441 regulator is a relatively complex circuit using 2 x 555
> > timers, 2 x LM301 op-amps, 2 x transformers and 2 inductors
> > I am struggling to understand how it is meant to work and was hoping to
> > find a maintenance manual for it.
> >
> > Could anyone with such a manual please help?
> >
> > Alternatively is there another explanation of the operation of this or
> > similar types of circuits?
> > The circuit implements a switch mode supply.
> >
> > One of the two 555 timers operates as an oscillator, the second I think
> > operates as a monoflop with the pulse length controlled via one of the
> > LM301s.
> > Overall the circuit seems very complex and while I understand parts of
> it,
> > other parts are mysterious.
> >
> > In particular the top left section around Q1/Q2/Q3 and T1/T2 and E3 is
> most
> > confusing.
> >
> > I did not find anything remotely similar in "The Art of Electronics" from
> > Horowitz & Winfield.
> >
> > The H7441 schematics are available from here:
> >
> >
> https://deramp.com/downloads/mfe_archive/011-Digital%20Equipment%20Corporation/08%20PDP-11/01%20PDP-1104-1134/02%20PDP-1134A%20Power%20Supply/H7441%20FMPS%20MP00271%20part-1%20(H7441).pdf
> >
> > Thanks for any help or suggested reading material.
>
>
>
> I'll take a stab at a brief description:
>
> The basic form is that of a switching inductive buck/step-down regulator.
>
> L1 is the main bucking inductor.
> D12 is the inductor discharge diode for the bucking operation.
> Q1 and Q2 are the main switching transistors, operating in parallel with
> T2 in their emitter circuits to balance current through the two transistors.
> Q3 is a driver stage for Q1,Q2.
> C11,L2,C16 are the main output filter.
>
> Fixed-frequency oscillator E1 triggers variable-width monostable E2 via Q6
> to create the PWM switching pulses.
> Q8 and associated form a constant-current source for the timing capacitor
> C10 of this PWM-monostable, to linearize the charge curve of the capacitor
> for better operation of the pulse-width timing.
>
> The switching pulses from the PWM-mono are amplified by Q5 to drive T1.
> T1 provides galvanic (voltage) isolation to shift the pulses up to the
> higher operating voltage of Q1,Q2,Q3.
> All base-drive energy for Q1 and Q2 is delivered through Q3 from T1, thus
> Q5 driving T1 must itself be a reasonably hefty driver.
> Excessive current through Q5 produces a V-drop across R10 which may turn
> on Q7 to take the PWM-mono into reset (E2.4=low).
> D7,D8,R3 clamp and sink reverse voltage/energy from the T1 secondary to
> avoid reverse breakdown/damage to Q1,Q2,Q3.
>
> Op-amp E4 is the voltage-sense amplifier for the main regulation feedback
> loop.
> D18 and associated provide the master reference voltage.
> An increase in the sensed +5 output voltage presented at -input E4.2
> relative to the reference voltage at +input E4.3 lowers the voltage into
> the PWM-mono control input E2.5 to shorten the ON-width of the switching
> pulses, and vice-versa for a decrease in the +5 output.
>
> Op-amp E3 is running open-loop to function as a comparator for
> over-current sense.
> R17,R18 are the current-sense resistors, placed here in the negative
> supply line of the +5 main output.
> If the current-induced voltage drop across R17,R18 becomes high enough, E3
> trips high, turning on Q7 to take the PWM-mono into reset.
> R19,R20 provide the counter-bias V that the R17,R18 V-drop must overcome
> to trip E3.
> E3 tripping high also turns on Q9 to short the reference voltage to GND at
> E4.3, to minimize the ON-width of the switching pulses.
>
> D20,D21,D22 form a crowbar for the +5 output.
> The crowbar tripping performs two actions: shorting the +5 output via D19,
> as well as shorting the switching pulses at the base of Q5 via D23 so the
> supply doesn't keep pumping energy into the shorted output.
>
> D2,Q4 and associated form a simple linear regulator for internal supply of
> ~ +12V to the control electronics.
> C7,D17,D25,C8 are a little charge pump driven off oscillator E1 to create
> a negative V supply for the op-amps E3,E4.
>
>

[cctalk] Theory of operation of DEC H7441 regulator?

[Tom Hunter via cctalk]

The DEC H7441 regulator is a relatively complex circuit using 2 x 555
timers, 2 x LM301 op-amps, 2 x transformers and 2 inductors
I am struggling to understand how it is meant to work and was hoping to
find a maintenance manual for it.

Could anyone with such a manual please help?

Alternatively is there another explanation of the operation of this or
similar types of circuits?
The circuit implements a switch mode supply.

One of the two 555 timers operates as an oscillator, the second I think
operates as a monoflop with the pulse length controlled via one of the
LM301s.
Overall the circuit seems very complex and while I understand parts of it,
other parts are mysterious.

In particular the top left section around Q1/Q2/Q3 and T1/T2 and E3 is most
confusing.

I did not find anything remotely similar in "The Art of Electronics" from
Horowitz & Winfield.

The H7441 schematics are available from here:

https://deramp.com/downloads/mfe_archive/011-Digital%20Equipment%20Corporation/08%20PDP-11/01%20PDP-1104-1134/02%20PDP-1134A%20Power%20Supply/H7441%20FMPS%20MP00271%20part-1%20(H7441).pdf

Thanks for any help or suggested reading material.

Tom

[cctalk] Re: PDP-8/L $15,000

[Tom Hunter via cctalk]

I have one Interprocessor Buffer (M8326). Of course just one won't help to
connect my Lab-8/e and my PDP-8/e.   :-(

On Thu, 31 Aug 2023, 12:49 am Mike Katz via cctalk, 
wrote:

> DEC did make the Interprocessor Buffer (M8326) for the Ominibus. That
> allowed for relatively high speed communications between machines.  You
> could also do some kind of serial network like Lantastic.I know some
> company made an SDLC board set for the omnibus.
>
> On 8/30/2023 8:04 AM, Paul Koning via cctalk wrote:
> >
> >> On Aug 29, 2023, at 8:46 AM, Chris Zach via cctalk <
> cctalk@classiccmp.org> wrote:
> >>
> >>
> >>> -BUT- That does not mean it *can't* be restored, only that $15,000 is
> >>> ridiculous for a machine that clearly needs an expert with time and
> money.
> >>> b
> >> True, it is a silly price. I was thinking about this on the forum: If
> someone offers to buy one of my fully running 8/L's for 6k I'll put in an
> offer on this one for 3k and restore it. The extra 3k will be used to buy
> beer to help me forget about all of the little mouse ghosts I'm going to
> find. :-)
> >>
> >> I'd offer 3k for it outright, but to be honest I can't have 3 pdp8/L's
> AND an 8/e. At some point I'd have to wire them into some sort of nightmare
> SMP pdp8
> > Or DECnet/8, though I suspect an 8/L can't run that.
> >
> >   paul
> >
>
>

[cctalk] Re: PDP-8/L $15,000

[Tom Hunter via cctalk]

My trick for successful landing the CDC Cyber/6000 series lunar lander
version was to set the initial height above the moon's surface to the
minimum height of 1' and then let it drop. I never successful landed from
the default height above the surface. It was seriously difficult.

On Tue, 29 Aug 2023, 5:06 am Paul Koning via cctalk, 
wrote:

>
>
> > On Aug 28, 2023, at 4:55 PM, Will Cooke via cctalk <
> cctalk@classiccmp.org> wrote:
> >
> >
> >
> >> On 08/28/2023 3:48 PM CDT Paul Koning via cctalk 
> wrote:
> >>
> >> Lander, in FOCAL? The only one I know is for the GT40, in assembler.
> >>
> >> paul
> >
> > Apparently the original version was in FOCAL.
> > https://www.cs.brandeis.edu/~storer/LunarLander/LunarLander.html
> >
> > Will
>
> Interesting.  And amazingly short.
>
> I flipped through some of those articles.  There's a version from around
> those early times not mentioned, for the CDC 6000 mainframe computer.  It
> used the console display, dual green text displays that could also do
> graphics (clumsily, because the API was a dot drawing one, not line
> vectors).
>
> What's unusual about that one is that it's a pilot's point of view display
> -- it shows you the lander's instruments and a view out the windows, rather
> than an outside observer view as the GT40 version does.  I played it a few
> times, it was hard -- I never managed to land it.  One of the system staff
> (at University of Illinois PLATO project) was rumored to have a fast way to
> land: flip upside down, blast rockets, flip right side up, blast some more
> for a soft landing.
>
> paul
>
>

[cctalk] Re: PDP-8/L $15,000

[Tom Hunter via cctalk]

Look at the photos. Let it rust in peace in mouse heaven. It is just scrap.


On Tue, 29 Aug 2023, 1:30 am Bill Degnan via cctalk, 
wrote:

> It can be yours for only $15,000 plus shipping
> https://www.ebay.com/itm/126067408991
>
> sheesh.
>
> Bill
>

[cctalk] Re: Digilent Coolrunner-II eval kit?

[Tom Hunter via cctalk]

Hi Tom,

I have a Xilinx CoolRunner-II Design Kit from 2002. It was made by
Digilent. On the silk screen it says Digilab XC2.
You are welcome to have it for the cost of postage from Australia.

Best regards
Tom Hunter

On Thu, Aug 24, 2023 at 2:40 AM Tom Uban via cctalk 
wrote:

> I am looking for a Digilent Coolrunner-II evaluation kit. If anyone has
> one they would be willing to
> part with, please let me know...
>
> --tnx
> --tom
>
>

[cctalk] Re: VT100: Datasheet for Intel 8228

[Tom Hunter via cctalk]

Common DSO trigger problems experienced by a novice are:

1) Trigger position is off the screen. The trigger position relative to the
current visible capture is typically shown somewhere on the screen - often
at the top of the screen. Reduce the horizontal resolution to something
like 10 ms/division and then scroll the trigger position to be in the exact
centre of the screen and then increase the horizontal resolution to
something suitable e.g 500 ns/division. Typically the DSO will keep the
trigger position centred if you had it close enough to the centre position
before increasing the horizontal resolution.

2) The horizontal resolution is set so that the pulse is invisible. For
example 1 ms/division for a 10 ns pulse.

3) Triggering on the wrong channel.

4) Trigger level above or below the signal.

5) Trigger mode set to "Auto" as opposed to "Normal" or "Single" causing a
momentary display of the triggered signal which is immediately overwritten
by the current signal.

Tom Hunter

On Mon, Jul 17, 2023 at 1:14 AM Rob Jarratt via cctalk <
cctalk@classiccmp.org> wrote:

> I used a logic analyser to check the 8228 and it does appear to be working
> as expected as can be seen here
> https://rjarratt.files.wordpress.com/2023/07/8228-operation.jpg. The
> labels are not very clear, but the 3rd from top is the WR input and the 4th
> from top is the I/O W output. So it does look like it is working.
>
> The odd thing is that I can't pick this up with my DSO. I have tried
> messing with the trigger, but I just can't pick up anything that shows I/O
> W going low. I am using -ve edge triggers. I have tried a pulse trigger
> with a width >20ns and I have tried nth edge trigger, neither of the latter
> two ever trigger. Obviously it is my method that is wrong, but I really
> don't know what it is about my method that is wrong. Are there any common
> mistakes that novices make?
>
> Thanks
>
>
>

[cctalk] Re: Greaseweazle part 2

[Tom Hunter via cctalk]

Is it really necessary to be always so confrontational? It is unpleasant.

On Sun, 11 June 2023, 10:44 pm Tony Duell via cctalk, 
wrote:

> > Fundamentally, it seems to me that they're all the same basic hardware,
> > timing intervals between flux transitions.
> >
> > So other than the soaftware, what's the difference?
>
> I could make a stupid comment and ask 'what's the difference between a
> PDP8, PDP11, PERQ or HP9830?'. Apart from having finite memory, all
> are (I believe) equivalent to a Turing machine.
>
> But more seriously when I started asking about writing images to
> floppy disks, I asked what options were available and what I'd need.
> Apart from the (IMHO) stupid suggestion of a 1990's PC compatible, the
> only thing that was mentioned to me was the Greaseweazle. Nobody
> pointed me at web sites giving comparisons between the various methods
> and devices.
>
> -tony
>

[cctalk] Re: One of Paul Allen's Museums

[Tom Hunter via cctalk]

Hopefully the LCM will be sold as a going concern rather than just a
firesale of the assets.
Otherwise a lot of donors and contributors would be rightfully upset - me
included.
I am disappointed that Bill Gates hasn't bought it already to continue
Paul's vision.
Tom

On Mon, Apr 24, 2023 at 11:30 PM Chuck Guzis via cctalk <
cctalk@classiccmp.org> wrote:

> On 4/24/23 03:18, Pete Turnbull via cctalk wrote:
> > On 24/04/2023 06:45, ED SHARPE via cctalk wrote:
> >> Bad link  Zane I get a weird  screen from the timeEd#
> >
> > Delete the strange character after the last "/" and it will work:
> >
> >
> https://www.seattletimes.com/business/boeing-aerospace/after-3-years-flying-heritage-museum-to-reopen-in-everett/
>
> As I understand the situation, Jody, Paul's sister, is the named
> executor for Paul's assets.  I've read that his instructions were to
> sell off most of the assets and donate the proceeds to charity.  In
> other words, the LCM will be sold; whether or not it remains intact is a
> decision made by the purchaser.
>
>
> --Chuck
>
>
>

[cctalk] Re: Mail veracity signing

[Tom Hunter via cctalk]

It got all the way Down Under.  8-)


On Fri, 21 Apr 2023, 8:56 am Zane Healy via cctalk, 
wrote:

> That was rather my thought, it made it through.
>
> Zane
>
>
>
>
> > On Apr 20, 2023, at 5:38 PM, Paul Koning via cctalk <
> cctalk@classiccmp.org> wrote:
> >
> > Your note got through, that's a promising start.  Let's hope this change
> helps.
> >
> >   paul
> >
> >> On Apr 20, 2023, at 8:32 PM, Dennis Boone via cctalk <
> cctalk@classiccmp.org> wrote:
> >>
> >> Folks,
> >>
> >> A heads up that I've turned on some mail veracity signing functionality
> >> in Mailman.  One could hope it would just work, and that I made no
> >> mistakes in the configuration, but... :)
> >>
> >> I'm working on this to try to improve deliverability of list traffic.
> >>
> >> De
> >
>
>

[cctalk] Re: Schematics for Lear Siegler ADM31?

[Tom Hunter via cctalk]

... or four $20 power transistors to protect a 10 cent fuse like on the DEC
VR-14 display.
Tom

On Wed, 19 Apr 2023, 6:16 am Fred Cisin via cctalk, 
wrote:

> On 2023/04/18 9:40 a.m., Tony Duell wrote:
> > The blown out resistor likely has "blown out" for a reason.
> > The replacement will probably suffer the same faith unless you find the
> > root cause.
>
> Isn't there usually a larger, more critical component, such as a
> proprietary microprocessor, to blow out to protect the resistor?
>
>

[cctalk] Re: HP9825A for sale

[Tom Hunter via cctalk]

The Ebay listing hasn't sold but has been relisted at the same price.


On Tue, Apr 18, 2023 at 12:16 AM John Robertson via cctalk <
cctalk@classiccmp.org> wrote:

> On 2023/04/17 9:12 a.m., Sellam Abraham via cctalk wrote:
> > My initial reaction is that $2,000 seems a "bit" optimistic.
> >
> > That being said, I'm surprised to see (on eBay's Terapeak) a couple of
> > these sold within the past year for around $1,100.
> >
> > Sellam
>
> One sold on eBay for $2492USD...Apr 6, 2023:
>
> https://www.ebay.com/itm/225512121074?hash=item348191e2f2
>
> John :-#)#
>
> >
> > On Mon, Apr 17, 2023, 8:52 AM Steve Lewis via cctalk <
> cctalk@classiccmp.org>
> > wrote:
> >
> >> There is a gentlemen in New Jersey willing to sell his HP9825A
> >>
> >> I believe he is the original owner.  It has 4 ROM cartridges (that go in
> >> the front) and several data cartridges for the slot on the top left.
> >>
> >> He is asking $2000 but can probably negotiate (as he didn't find any
> takers
> >> in VCF East).  As far as he knows, everything still works (LED lights
> came
> >> on when he powered it up a few months ago).
> >>
> >> I've met this seller and can vouch for him, but I don't know much about
> >> this particular item.
> >>
> >> I have some photos of it at the bottom of this page:
> >> https://voidstar.blog/vcf-east-2023-part-3/
> >>
> >> I may try a VCF forum topic about it.  Just trying to help him find a
> good
> >> home for the equipment.  E-mail/reply direct and I can provide some
> contact
> >> info.
> >>
> >> (BTW not sure if my cctalk posts are working anymore??)
> >>
> >> -Steve / voidstar
> >>
>
> --
>   John's Jukes Ltd.
> 7 - 3979 Marine Way, Burnaby, BC, Canada V5J 5E3
> Call (604)872-5757 (Pinballs, Jukes, Video Games)
>   flippers.com
>   "Old pinballers never die, they just flip out"
>
>

[cctalk] Re: Schematics for Lear Siegler ADM31?

[Tom Hunter via cctalk]

The blown out resistor likely has "blown out" for a reason.
The replacement will probably suffer the same faith unless you find the
root cause.

On Tue, Apr 18, 2023 at 12:20 AM John Robertson via cctalk <
cctalk@classiccmp.org> wrote:

> I've checked bitsavers.org (Al does a great job!), and a number of
> forums, but no luck finding schematics for my ADM31 that I am trying to
> resurrect. The power supply has issues and I need to identify a blown
> out resistor - the switching supply is a Boschert model 1001 date code
> 7943 Revision J.
>
> John :-#)#
>
> --
>   John's Jukes Ltd.
> 7 - 3979 Marine Way, Burnaby, BC, Canada V5J 5E3
> Call (604)872-5757 (Pinballs, Jukes, Video Games)
>   flippers.com
>   "Old pinballers never die, they just flip out"
>
>

[cctalk] DEC M8340 board

[Tom Hunter via cctalk]

Does anyone have a surplus DEC M8340 board with PCB etch level E and
revision F (as imprinted on the handle)?

If yes, please reply to thunter6...@gmail.com.



Thanks and best regards

Tom Hunter

[cctalk] Re: TREK7 is back! - TREK7 FORTRAN Multi-User Game (PDP-10/VAX) Revived

[Tom Hunter via cctalk]

I have uploaded a ZIP file with the FORTRAN IV sources of Startrk, Aventure
and Qork to Google Drive.
These are CDC CYBER mainframe versions for the NOS operating system.
Adventure and Qork each come with a text file used by the game.

Here is the link to the file "games.zip":

https://drive.google.com/file/d/1Sr53cfBEkNGwsauzIKAp_5ZDnaFGT9WN/view?usp=sharing

Have fun.
Tom


On Sat, Apr 1, 2023 at 10:00 AM Eric Moore  wrote:

> Awesome! Thank you! I also received a link to a fortran 4 copy of
> adventure. Now to spend months or years trying to punch, read, compile, and
> run it 
>
> On Fri, Mar 31, 2023, 8:49 PM Tom Hunter via cctalk 
> wrote:
>
>> I am pretty sure I have a FORTRAN IV version of it running on CDC CYBER
>> and
>> 6000 series mainframes. I will dig it up next time I fire up the emulator.
>> Tom
>>
>> On Fri, 31 Mar 2023, 8:59 pm Eric Moore via cctalk, <
>> cctalk@classiccmp.org>
>> wrote:
>>
>> > Congrats! I am looking for star trek for fortran 4 if anyone knows
>> where it
>> > is.
>> >
>> > Thanks,
>> >
>> > -Eric
>> >
>> >
>> > On Fri, Mar 31, 2023, 7:52 AM Hans-Ulrich Hölscher via cctalk <
>> > cctalk@classiccmp.org> wrote:
>> >
>> > > The Star Trek simulation game TREK7 was written in FORTRAN by Donald
>> M.
>> > > Ecclestone in the early 70ties for the PDP-10.
>> > >
>> > > The game was ported to VAX computers running VMS in 1978 by the author
>> > with
>> > > the help of Dan Gahlinger.
>> > >
>> > > For some years TREK7 fell into a deep slumber until in 1993 Dan
>> Gahlinger
>> > > decided to revive it, but some severe bugs remained, hindering any
>> > > successful round of game.
>> > >
>> > > Last year I began to work on the problems still present in TREK7.
>> > >
>> > > After detecting and fixing more than 60 bugs (mostly caused by
>> > > transcription errors) step by step, the game is playable again now.
>> > >
>> > > Dan Gahlinger backed out of the project and I am the maintainer of
>> TREK7
>> > > now.
>> > >
>> > > For details see: https://gunkies.org/wiki/TREK7
>> > >
>> > > Former TREK7 players please give me a shout!
>> > >
>> > > Ulli
>> > > The VAXorcist
>> > >
>> >
>>
>

[cctalk] Re: TREK7 is back! - TREK7 FORTRAN Multi-User Game (PDP-10/VAX) Revived

[Tom Hunter via cctalk]

I am pretty sure I have a FORTRAN IV version of it running on CDC CYBER and
6000 series mainframes. I will dig it up next time I fire up the emulator.
Tom

On Fri, 31 Mar 2023, 8:59 pm Eric Moore via cctalk, 
wrote:

> Congrats! I am looking for star trek for fortran 4 if anyone knows where it
> is.
>
> Thanks,
>
> -Eric
>
>
> On Fri, Mar 31, 2023, 7:52 AM Hans-Ulrich Hölscher via cctalk <
> cctalk@classiccmp.org> wrote:
>
> > The Star Trek simulation game TREK7 was written in FORTRAN by Donald M.
> > Ecclestone in the early 70ties for the PDP-10.
> >
> > The game was ported to VAX computers running VMS in 1978 by the author
> with
> > the help of Dan Gahlinger.
> >
> > For some years TREK7 fell into a deep slumber until in 1993 Dan Gahlinger
> > decided to revive it, but some severe bugs remained, hindering any
> > successful round of game.
> >
> > Last year I began to work on the problems still present in TREK7.
> >
> > After detecting and fixing more than 60 bugs (mostly caused by
> > transcription errors) step by step, the game is playable again now.
> >
> > Dan Gahlinger backed out of the project and I am the maintainer of TREK7
> > now.
> >
> > For details see: https://gunkies.org/wiki/TREK7
> >
> > Former TREK7 players please give me a shout!
> >
> > Ulli
> > The VAXorcist
> >
>

[cctalk] Re: Knockoffs, was: Low cost logic analyzer

[Tom Hunter via cctalk]

FSF does not enforce anything. I repeatedly begged for help with Desktop
CYBER which was GPL licensed and they did not even bother to reply.

Tom Hunter

On Thu, Mar 16, 2023 at 7:46 AM Paul Koning via cctalk <
cctalk@classiccmp.org> wrote:

>
>
> > On Mar 14, 2023, at 10:57 PM, Jonathan Chapman via cctalk <
> cctalk@classiccmp.org> wrote:
> >
> >> If you posted your design as Open Source, someone else producing it
> isn't a knockoff, it's the system working as intended.
> >
> > What is it when the design is open source, but they're not complying
> with the terms of the license? That's what really bugs me, the "cost" of
> producing your own from one of our designs is attribution and releasing
> your design under the same or a compatible license, but apparently that's
> too much to ask.
> >
> > Thanks,
> > Jonathan
>
> You're talking about GPL or equivalent there -- for which the FSF has at
> times been the enforcer.  BSD style licenses require next to nothing of
> people copying (in particular, they don't require releasing the derived
> work).
>
> Personally I'm partial to BSD style licenses, though some of my open
> source work was originally licensed under GPL.  (I may change that at some
> point if I want to bother.)  That means I'm accepting the possibility that
> someone could copy what I did and sell it as a closed product.  Fine, so be
> it (that doesn't close what I did, of course).
>
> paul
>
>

[cctalk] Re: Low cost logic analyzer

[Tom Hunter via cctalk]

Be careful about throwing stones if you are living in a glass house.


On Tue, 14 Mar 2023, 6:49 pm Peter Coghlan via cctalk, <
cctalk@classiccmp.org> wrote:

> >
> > There are some nice mixed signal oscilloscopes made by Rigol (Chinese)
> at a
> > very affordable price.
> >
>
> Until just over a year ago, buying very afforadable Russian oil and gas
> also
> seemed like a great idea with no downsides compared to getting these
> products
> elsewhere.
>
> Regards,
> Peter Coghlan.
>

[cctalk] Re: Low cost logic analyzer

[Tom Hunter via cctalk]

There are some nice mixed signal oscilloscopes made by Rigol (Chinese) at a
very affordable price. They have a very deep capture buffer for both analog
and digital signals. The build quality and capabilities of the MSO1104Z I
have are outstanding. I got all the options included for free as a special
offer (various decoding options, increased capture buffer depth, etc). IIRC
none of the Rigol mixed signal scopes have more than 16 digital channels,
but I never really needed more. There is an excellent review including
teardown on David Jones' eevblog. All logic analysers I have used had a
trigger output so that you can cascade multiple different ones to increase
the number of channels captured. The only problem I can see with less than
32 channels would be if you have to trigger on a specific combination
involving all 32 bits. Even that could be solved by a bit of external logic
if you are desperate enough.
Tom Hunter

On Tue, 14 Mar 2023, 9:12 am Paul Koning via cctalk, 
wrote:

> Gents,
>
> I've been doing logic debugging (on a fairly primitive software defined
> radio I designed back in 1999) with an old Philips logic analyzer.  It's
> not bad, certainly fast enough (I need 100 Msamples/s, it can do twice
> that) and it's more than wide enough (I need 32 channels).  But its capture
> memory is microscopic so I struggle to see more than one or two
> transactions, and I need to see more than that.
>
> Some poking around shows various USB-connected logic analyzers for quite
> low prices, and a number of them seem to have suitable specs.  I also ran
> across sigrok.org which seems to be an open source logic analysis
> framework that can drive a bunch of those devices.  Nice given that too
> many of them only come with Windows software.
>
> I suspect there are others that have not too expensive logic analyzers and
> might be able to offer up suggestions or product reviews.
>
> paul
>
>

[cctalk] Re: WTB Any storage for a PDP 8/A

[Tom Hunter via cctalk]

Thank you very much Vince.


On Sun, 26 Feb 2023, 3:48 pm Vincent Slyngstad via cctalk, <
cctalk@classiccmp.org> wrote:

> On 2/25/2023 10:46 PM, Tom Hunter via cctalk wrote:
> > Hi Vince,
> >
> > Could you please point us to the Makefile which "actually converts a disk
> > image" using SIMH to "automate the ritual of unistalling RK05 drivers and
> > replacing them with SerialDisk drivers"?
>
> Ah, I seem to have misspoken.  Inspecting the Makefile in .../installer,
> it still runs the executable "handler_installer", which is the older
> tool that more or less just hammers a new system handler and bootstrap
> into place.
>
> The script for the new installer is "sdsk".  This sets up a path for the
> tools, copies the newest driver binaries into the exploded disk image
> (while padding them to an even block length), then imploding the
> exploded directory and making a new bootable RK05 image.
>
> Then "runbuild" is invokes, which in turn invokes SIMH and sends a
> series of commands to BUILD.SV to remove various other drivers and
> install the "SDSKSY" and "SDSKNS" drivers copied above.  Finally, the
> "BOOT" command is given to write the new second stage (and third stage)
> bootstrap.  The self-modified BOOT.SV is also saved as BUILT.SV.
>
> Sorry for the confusion.
>
> If you don't want to use diagpack2, SDSK.md is helpful, but basically
> you need to edit the line:
> image=diagpack2
> in the sdsk script, and to have previously copied in your starting
> image, and run ../tools/os8xplode on it.  SDSK.md also contains
> information about the need for "perl", "socat", and "expect" and to get
> them (on Linux, anyway).
>
> Oh, and the SIMH initialization file (pdp8.ini) is also firing up the
> server program, so you need to tweak that to make your "foo.new"
> available to the SIMH serial emulation.  That script used to also
> require a functioning xterm, but it doesn't any more.  If you have xterm
> and want to see the server log in real time, there are lines there to
> invoke ../server/server the other way, and you can un-comment that and
> comment out the bash line.
>
> Once you've done all the above, it suffices to just type "pdp8" in that
> directory and your new system should boot in SIMH.
>
> Hope that helps,
>
> Vince
>
> > On Sun, Feb 26, 2023 at 2:34 AM Vincent Slyngstad via cctalk <
> > cctalk@classiccmp.org> wrote:
> >
> >> ...
> >>
> >> The one I use most uses the SIMH simulator to automate the ritual of
> >> uninstalling RK05 drivers and replacing them with SerialDisk driver.
> >> The Makefile there will actually convert a disk image, and you could
> >> just swipe the default one once it's been made.
> >>
> >>
>
>

[cctalk] Re: WTB Any storage for a PDP 8/A

[Tom Hunter via cctalk]

Hi Vince,

Could you please point us to the Makefile which "actually converts a disk
image" using SIMH to "automate the ritual of unistalling RK05 drivers and
replacing them with SerialDisk drivers"?

Thanks
Tom

On Sun, Feb 26, 2023 at 2:34 AM Vincent Slyngstad via cctalk <
cctalk@classiccmp.org> wrote:

> ...
>
> The one I use most uses the SIMH simulator to automate the ritual of
> uninstalling RK05 drivers and replacing them with SerialDisk driver.
> The Makefile there will actually convert a disk image, and you could
> just swipe the default one once it's been made.
>
>

[cctalk] Re: Store with "vintage" computers and parts

[Tom Hunter via cctalk]

Ok as Google search is increasingly failing us, what other search engine
should I use?

Tom

On Fri, 10 Feb 2023, 3:28 am Angel M Alganza via cctalk, <
cctalk@classiccmp.org> wrote:

> On 2023-02-09 15:31, Eric Moore via cctalk wrote:
>
> > If in doubt, GOOGLE THE WEBSITE, and see if valid websites link to it,
> > if
> [...]
> > Stay safe out there :)
>
> In my opinion, one of the first things to do to try to stay safe out
> there, if not the first, is to stop using that website and use one that
> doesn't track what you search, that doesn't show you different results
> to what it shows to other people who do the same search, and that
> doesn't treat you as its product.
>
> Cheers,
> Ángel
>

[cctalk] Re: Store with "vintage" computers and parts

[Tom Hunter via cctalk]

Avast claims the site is infected with a trojan.
The contact address does not exist: 4144 Fannie Street Houston, Texas 77063
United States
Stay away!

On Thu, Feb 9, 2023 at 2:59 PM Sellam Abraham via cctalk <
cctalk@classiccmp.org> wrote:

> This is an item I had listed on eBay for a couple years, and which sold on
> eBay a few months ago ==>
>
> https://www.bryanipad.shop/product/dsp-225-tempest-ink-jet-printer-hp-2225a-thinkjet-in-rf-shielded-enclosure-737796124001173505.html
>
> The photos and description are mine, from my eBay ad.
>
> This is definitely a scam.
>
> Sellam
>
> On Wed, Feb 8, 2023 at 8:21 PM Steven Shumaker via cctalk <
> cctalk@classiccmp.org> wrote:
>
> > interesting!  Some of the items looked really familiar so I did some
> > quoted text searches on EPay.   They were exact matches for some highly
> > unique listings
> >
> > who is scamming who here...
> >
> > Steve
> >
> >
> >
> > On 2/8/2023 7:47 PM, Glen Slick via cctalk wrote:
> > > On Wed, Feb 8, 2023 at 7:17 PM Will Cooke via cctalk
> > >  wrote:
> > >> This place may be of interest.  Most of the stuff they have for sale
> > probably isn't of much interest here, but there are a few gems.  The link
> > takes you to one, which is how I found it.
> > >>
> >
> https://www.bryanipad.shop/product/microlog-corporation-atr-6800-vintage-rare-738148146177114113.html
> > >>
> > > Very skeptical that this site is legitimate.
> > >
> > > "Free Shipping & Returns: Free Shipping for all orders. Free Return"
> > > Uh, no way, no how.
> > >
> > > Reviews are just some Lorem Ipsum text.
> > >
> > > 1 Review For Chaz Kangeroo Hoodies
> > > Admin - 30 Nov, 2018
> > > Aliquam fringilla euismod risus ac bibendum. Sed sit amet sem varius
> > > ante feugiat lacinia. Nunc ipsum nulla, vulputate ut venenatis vitae,
> > > malesuada ut mi. Quisque iaculis, dui congue placerat pretium, augue
> > > erat accumsan lacus
> >
>

[cctalk] Re: Nuking an MFM drive with a magnet, format/servo gone?

[Tom Hunter via cctalk]

Chris, what kind of magnet did you use?
If it was an electromagnet I could imagine that you caused physical damage
by something heating up sufficiently. If it was a permanent magnet then it
might indeed be servo data which has been erased. Either way I expect you
need a very strong magnetic field to erase a hard drive from the outside.
Tom

On Sat, 4 Feb 2023, 12:40 am Chris Zach via cctalk, 
wrote:

> Question: I just used a strong magnet to wipe an old Maxtor MFM drive
> (magnet on outside of case). Now the drive will not even seek properly
> on start up, just endlessly moves the heads..
>
> Is the drive now toast? Do MFM drives have embedded servo information on
> the platter formatted by the factory?
>
> CZ
>

[cctalk] Re: Computer Museum uses GreaseWeazle to help exonerate Maryland Man

[Tom Hunter via cctalk]

Chuck, the CDC 7600 duty cycle integrator is really a work-around against
overheating and has nothing to do with core reliability and/or endurance.

Core and the data stored in it lives "forever" if the operating constraints
of the medium are adhered to (temperature being one of the constraints).
The 7600 was able to push core access past these constraints, hence needed
the duty cycle integrator. Different physical design and/or better cooling
could have been alternatives, but the duty cycle integrator was an easy fix
once the machine was out in the field and core memory started failing due
to overheating.

Core written in the 60s would read just fine today unless something
external to it destroyed the data.

Tom

On Fri, Feb 3, 2023 at 2:12 PM Chuck Guzis via cctalk 
wrote:

> On 2/2/23 21:23, Tom Hunter via cctalk wrote:
> > The actual ferrite core doughnuts do not break down with continued use,
> BUT
> > moisture or mechanical impact or vibration will damage or degrade the
> > ferrite cores. Otherwise the ferrite doughnut will live and maintain its
> > properties "forever".
>
> Well, I don't know about that.  The CDC 7600 had issues with core
> overheating and included a "Duty Cycle Integrator" on core.  See PDF
> page 51, page 2-24:
>
>
> http://www.bitsavers.org/pdf/cdc/cyber/cyber_70/60367200D_Cyber70-76_Jul75.pdf
>
> --Chuvk
>
>
>

[cctalk] Re: Computer Museum uses GreaseWeazle to help exonerate Maryland Man

[Tom Hunter via cctalk]

The actual ferrite core doughnuts do not break down with continued use, BUT
moisture or mechanical impact or vibration will damage or degrade the
ferrite cores. Otherwise the ferrite doughnut will live and maintain its
properties "forever".

The main cause of core memory mat faults is mechanical strain on the X/Y,
sense and inhibit wires.
This mechanical strain is caused by use and can be made worse by particular
usage patterns causing the core memory mat to vibrate producing an audible
ring. CDC's Extended Core Storage (ECS) cabinets had a characteristic sound
when you opened the doors.

Early on CDC 6000 series machines had a lot of reliability problems with
core memory, but eventually there was an ECO where the core memory modules
were immersed in potting compound to make the core mat rigid to prevent any
vibration. This made the once fragile core perform perfectly for the
remaining life of the machine.

The core memory in my PDP-8/e machines (H212 board) has the ferrite donuts
glued to the PCB via some white adhesive presumably to reduce vibrations.
Encasing the core mat in potting resin would have been the better solution
as it binds the wires to the ferrite doughnuts.

Tom

On Thu, Feb 2, 2023 at 11:17 PM Jon Elson via cctalk 
wrote:

> On 2/1/23 22:10, Will Cooke via cctalk wrote:
> >
> >> On 02/01/2023 3:51 PM CST Paul Koning via cctalk 
> wrote:
> >>
> > ot sure about that. What sort of numbers are we talking about?
> >> If all else fails there's core memory, which as far as I remember is
> pretty much unlimited for both read and write.
> >>
> >> paul
> > I don't know for sure and can't find any references, but I strongly
> suspect that core memory would wear out over time, as well.  My reasoning
> for this is the because in principle it works the same as FRAM.  I usually
> refer to FRAM as "core on a chip."  Over time, the magnetic domains in FRAM
> tend to stay in one polarization or another.  I see no reason why the
> magnetic domains in core wouldn't do the same.  However, a single core is
> probably bigger than the entire FRAM chip so there are a LOT more domains.
> That means it would take a proportional amount of writes to wear out --
> let's just say a million times.  In addition, core access was in
> microseconds, whereas FRAM and other modern memories are in nanoseconds.
> So it takes something like 1000 times longer on the clock on the wall to
> perform the same number of writes.  So in the end something like a billion
> times longer on the calendar to wear it out.
> >
> > I would be very interested if anyone actually knows and especially if
> there are references available.
>
> I have extreme doubts that this is true.  Memory cores are
> just tiny versions of pulse transformers, and similar square
> loop transformer core materials are used in switching power
> supplies that run for decades at high switching
> frequencies.  Really, FRAM does not work much similarly to
> core.  The ferroelectric material is usually lead zirconate
> titanate, not an actual ferromagnetic material.  It is
> written by an electric field, not magnetic, and the electric
> field is sensed by a field effect transistor.  I have NEVER
> heard of core wear-out in magnetic core memories.  The
> flipping of the magnetic polarization in ferrite materials
> does not break down the crystal structure.
>
> Jon
>
> Jon
>
>

[cctalk] Re: windows reports contents of previous floppy

[Tom Hunter via cctalk]

Try supp...@microsoft.com

On Wed, 1 Feb 2023, 7:21 am Chris via cctalk,  wrote:

> why does this happen? how do I "reset" a floppy drive (in windows) so that
> it tells me what's on the current disk, not what was on the previous disk
> that's been removed.
>

[cctalk] Re: windows reports contents of previous floppy

[Tom Hunter via cctalk]

This is not the forum to ask MS Windows questions.

On Wed, 1 Feb 2023, 7:21 am Chris via cctalk,  wrote:

> why does this happen? how do I "reset" a floppy drive (in windows) so that
> it tells me what's on the current disk, not what was on the previous disk
> that's been removed.
>

[cctalk] Re: cctalk archives not updating

[Tom Hunter via cctalk]

Thanks David!

On Sun, Jan 29, 2023 at 2:07 AM David Gesswein via cctalk <
cctalk@classiccmp.org> wrote:

> Try the new archive
> https://classiccmp.org/mailman3/hyperkitty/list/cctalk@classiccmp.org/
>
> Linked to from the classiccmp page
> https://classiccmp.org/lists.html
>
> On Sat, Jan 28, 2023 at 02:51:15PM +0800, Tom Hunter wrote:
> > It appears that the cctalk archives stopped updating in July 2022. See
> the
> > link below:
> >
> > https://classiccmp.org/pipermail/cctalk/
> >
> > Could the new list admin please re-enable the archive feature of the
> > mailing list and if possible fill in the missing months since July 2022.
> >
> > Thanks and best regards
> > Tom
> >
> > --
>

[cctalk] cctalk archives not updating

[Tom Hunter via cctalk]

It appears that the cctalk archives stopped updating in July 2022. See the
link below:

https://classiccmp.org/pipermail/cctalk/

Could the new list admin please re-enable the archive feature of the
mailing list and if possible fill in the missing months since July 2022.

Thanks and best regards
Tom

[cctalk] DEC VR14 TO-3 heat-sink socket?

[Tom Hunter via cctalk]

 I finally got around to replace the dead TO-3 power transistors in my
VR-14. They are mounted on the power supply regulator heat sink using TO-3
sockets made by AUGAT. Unfortunately one of the sockets has been broken by
somebody in the past by over-tightening the transistor mounting screws.
This may have been the root cause of the power supply failure as one
transistor was doing all the work with the second transistor's collector
lead having poor or no connection. There are two NPN transistors in
parallel to double the power which is not a very good design anyway.

I am trying to find the original Augat sockets.

Here are some links to photos showing a closeup of the socket and the
threaded insert with the originally crimped collector tab which broke out
of the bakelite socket:

https://drive.google.com/file/d/1MXclwHLDmoz_P2ub7tPc9oqSgrDbnTzR/view?usp=sharing,


https://drive.google.com/file/d/1XJ7DpGA5Zx0ZSqDVL_gdBSWYuKdFHLlR/view?usp=sharing

I would be grateful for any help trying to source these AUGAT made TO-3
sockets. I had no luck finding stock of these with Google and Ebay.

Thanks and best regards
Tom

[cctalk] Re: Philips P2000C restoration

[Tom Hunter via cctalk]

Thank you Tony for your well written and informative post describing the
restoration of a Philips P2000C luggable.
I wish there would be more posts like yours.
Best regards
Tom

On Wed, Jan 25, 2023 at 12:57 AM Tony Duell via cctalk <
cctalk@classiccmp.org> wrote:

> Philip Belben gave me a Philips P2000C luggable CP/M computer some
> time back which had not been well-stored. It took a bit of work to get
> it going
> again. Here's what I did...
> ..
> -tony
>

[cctalk] Re: [SPAM] LINC-8 sells for $2,150

[Tom Hunter via cctalk]

You got an amazing bargain. I was expecting at least a magnitude higher
price.

On Fri, 20 Jan 2023, 8:29 am rar--- via cctalk, 
wrote:

> We (Computer Museum @ System Source) picked up this unit today.
> Here are a few snapshots after we pulled the unit off of the truck.
>
> https://photos.app.goo.gl/2GvqTQukSEEnyoQp8
>
> Bob Roswell
>

[cctalk] Re: long lived media (Was: Damage to CD-R from CD Sleeve

[Tom Hunter via cctalk]

One might ask what is really worth preserving for millenia? None of my
"treasures" qualify I think.
Tom

On Wed, 18 Jan 2023, 9:05 am Paul Koning via cctalk, 
wrote:

>
>
> > On Jan 17, 2023, at 3:34 PM, P Gebhardt via cctalk <
> cctalk@classiccmp.org> wrote:
> >
> >
> > Am Dienstag, 17. Januar 2023 um 15:54:54 MEZ hat Paul Koning via cctalk <
> cctalk@classiccmp.org> Folgendes geschrieben:
> >
> > ...
> >> I have an RM03 pack somewhere.  There probably are a few places left
> that could read it.  If it were an RA60 pack it would be a whole lot more
> problematic, I suspect.  Without an >old drive, how would you recover the
> data?  Spin table?  Perhaps, if you can find, or reverse engineer, the
> format.
> >
> > Do you assume the problem with RA60 disk packs to be more problematic
> because of a smaller availability of systems with RA60 drives to read the
> packs compared to CDC 9762 /RM03 drives?
>
> Yes, and the higher density, and the fact that the on-disk format is more
> complex and unlikely to be documented in any open documentation.
>
> paul
>
>
>

[cctalk] Re: Nova and Eclipse Emulator beta release

[Tom Hunter via cctalk]

G'day Bruce,

Fantastic news about your hobbyist licensed software and manuals and now
the Nova and Eclipse emulators becoming part of OpenSimh.
The Windows & Linux binary only releases were difficult for some of us.
I think now with an open-source emulator "Novas Are Forever" becomes a
reality.:-)

Best regards
Tom

On Fri, Nov 18, 2022 at 1:18 PM Bruce Ray via cctalk 
wrote:

> G'day Jay -
>
> > - You mention that the emulator combines "the SimH project structure"
> > with Wild Hare's commercial code.  I take this to mean that the emulator
> > is an extension of simh to support the listed DG processors and
> > devices.  Can you clarify which version (and ideally commit id) of simh
> > is this based on?
>
> OpenSimH rev 4, simh git commit id: 009d748a
>
> > - I noticed that the license document available on the dgbeta
> >  page only covers the legacy
> > software produced by DG.  Given the inclusion of commercial code in the
> > simh executables, can you clarify what license the emulator binaries are
> > released under? (Ideally this would be published along side the legacy
> > license text).
>
> The standard SimH structure is used and its license is honored.
>
> >
> > - Do you envision at some point publishing the simh emulator changes as
> > a pull request to the simh project (presumably under the simh license)?
>
> The new Nova and Eclipse emulator, along with the commercial components,
> will become part of the standard OpenSimH project and its license.
>
>
> > Again, thank you for your efforts here.  It's great to see this software
> > opened up to hobbyist use.
> > --Jay
> >
> >
> > On 11/10/2022 5:47 PM, Bruce Ray via cctalk wrote:
> >>
> >> Wild Hare Computer Systems is pleased to announce the public beta
> >> release of its Data General Nova and Eclipse emulator.
> >>
> >> This emulator allows the full range of DG 16-bit Nova and Eclipse
> >> computer software to run on Microsoft Windows and Linux platforms, and
> >> will become a major part of Wild Hare's increased efforts to preserve
> >> Data General's significant contributions to computer history.
> >>
> >> The emulator combines portions of Wild Hare's commercial products with
> >> the SimH project structure to create a single emulator for the 16-bit
> >> Nova and Eclipse computers.  The program supports a wide range of
> >> features, including:
> >>
> >> Processors:
> >>
> >> unmapped Nova, SuperNova, Nova 1200, Nova 800, Nova 2, Nova 3, Nova
> 4
> >> mapped Nova 840
> >> mapped Nova 3/D
> >> mapped Nova 4/X
> >> Eclipse S/130
> >> Eclipse S/140
> >> Eclipse S/150
> >> Eclipse S/120
> >> Eclipse Desktop Generation Model 20 and Model 30
> >>
> >>
> >> Peripherals:
> >>
> >> TTI/TTOprimary console (TeleType) input/output
> >> RTCreal-time clock
> >> TTI1/TTO1secondary console (TeleType) input/output
> >> PTRpaper tape reader
> >> PTPpaper tape punch
> >> PLTplotter
> >> LPTline printer
> >> MTAmag tape unit
> >> DSKfixed-head disks
> >> DKPmoving head disks
> >> DEPDesktop Generation disks
> >> DZPpopular "Zebra" moving head disks
> >> QTY4060 "Quad" asynchronous multiplexers
> >> ALM4255 Asynchronous Line Multiplexers
> >>
> >>
> >> Software:
> >>
> >> Operating Systems
> >>
> >> DOSNovas (first DOS written for Nova)
> >> URDOSRDOS for Novas and Eclipses (in unmapped mode)
> >> MRDOSRDOS for Mapped Nova 840
> >> NRDOSRDOS for Mapped Nova 3/D and Nova 4/X
> >> ZRDOSRDOS for Mapped Eclipses
> >> MP/OSNova 4
> >> DG/RDOSEclipses
> >> AOSEclipses
> >> MP/AOSEclipses
> >>
> >> Languages
> >>
> >> ASM (Assembler)
> >> MAC (Macro Assembler)
> >> ALGOL
> >> DG/L
> >> FORTRAN 4
> >> FORTRAN 5
> >> FORTRAN 77
> >> Extended BASIC
> >> Business BASIC
> >> MP Pascal
> >> SP Pascal
> >> COBOL
> >> Interactive COBOL (ICOBOL)
> >> PL/1
> >> RPG II
> >> IDEA
> >> INFOS II
> >> CEO
> >>
> >> Prior Data General knowledge is beneficial to using the emulator and
> >> corresponding DG software.  For convenience, Wild Hare has created
> >> container files of pre-configured operating system environments and
> >> their corresponding languages to minimize the time needed to enjoy the
> >> full DG "experience".
> >>
> >> This "beta-level" software release is intended to gather user feedback
> >> to help guide future product development.  Bug reports, comments,
> >> suggestions, ridicule and giggles can be sent to
> >> b...@wildharecomputers.com.
> >>
> >> Further information is contained in the emulator beta release web page:
> >>
> >> www.NovasAreForever.org/dgbeta
> >>
> >>
> >>
> >> Bruce Ray
> >> Wild Hare Computer Systems, Inc.
> >> 

[cctalk] Re: LC:M+L (Living Computer Museum)

[Tom Hunter via cctalk]

Thank you Rich for shedding light on this. Most of it makes sense to me,
but the secrecy part where you weren't allowed to talk to those still at
the museum is weird. I can't see any possible commercial reason for
preventing former engineering staff to talk with their former colleagues or
replacements. If anything you would think that any new staff would be
encouraged to talk to the engineers who left to benefit from their
experience. As I said this appears to be rather strange.

On Tue, 1 Nov 2022, 7:31 am Rich Alderson via cctalk, 
wrote:

> First, let me thank Sellam and Tom for inviting me to comment on this
> topic.
>
> LCM+L closed its doors to the public in March 2020, at the height of the
> initial pandemic (in the sense that it had become clear that the Covid-19
> virus
> was not a passing thing), because our entire mission was to make possible
> actual physical contact between visitors to the museum and vintage
> computing
> engines of various stripe.  There was no way to allow visitors to continue
> to
> touch all the hardware which would protect both visitors and the equipment.
>
> Tour guides and front desk personnel were immediately let go, because it
> was
> clear that it would be several months, up to a year, before we could open
> again.  Professional museum staff (curator, educational coordinator, etc.)
> were
> retained for a short while, to wind things down.  The engineers were put to
> work winding things down:  Creating power-down-bring-up documentation,
> backing
> up software on those systems for which that was necessary, and generally
> making
> it possible to close up shop with an eye to opening again in a year (the
> target
> period).
>
> This project was the response to the original order simply to turn
> everything
> off.  We pointed out vociferously how much damage that would do to the
> dinosaurs, reminding the nontechnical powers-that-be of just how long it
> had
> taken to make most of the vintage hardware work again, and that they could
> plan
> on a month of restoration per month of down time, before the museum could
> be
> reopened after the decision was made to do so.
>
> All of the engineers, which the exception of the manager of the department,
> were laid off as of 1 July 2020.  None of us was allowed to return to the
> museum at any future time, and no one associated with the mothballed
> museum was
> allowed to talk to any of us.
>
> All of that is by way of saying that I have no information on the internal
> state of the collection, or of the museum which we built on it.
>
> As for the status of the collection:  While we built the museum, there was
> a
> private foundation set up which acquired items for the collection,
> generally by
> purchase.  After 5 years of successful operations, with year over year
> increases in visitor counts, ongoing relationships with several school
> districts for instructional field trips, and worldwide acclaim, the
> decision
> was to taken to move to a 501(c)(3) public charity.  This transition was
> under
> way when Paul died suddenly; that placed things into limbo because the
> transition was incomplete, and the estate could not do things that he could
> have done in person.
>
> That's as much as I know.
>
> Rich
> Alderson
>
> P. S.  After the layoff, I looked for work for a few months, with nary a
>nibble.  I've officially been retired for tax purposes since
> September 2021.
>

[cctalk] Re: LC:M+L (Living Computer Museum)

[Tom Hunter via cctalk]

The Internet is wonderful for misinformation and a good laugh.
Here even Paul Allen's sister Jody can morph into Paul's wife.:-)

Rich Alderson please provide the LCM facts if you can to stop the silly
rumours.


On Mon, Oct 31, 2022 at 11:36 AM Michael Kerpan via cctalk <
cctalk@classiccmp.org> wrote:

> The museum had been one of Paul Allen's private passion projects. Sadly, he
> died rather unexpectedly and he hadn't really had time to set up a proper
> legal entity to protect it after his death, so it and all his other passion
> projects ended up controlled by his wife's real estate company which
> started looking at ways of shutting them down almost immediately. COVID
> gave them the perfect excuse, sadly.
>
> Mike
>
> On Sun, Oct 30, 2022, 1:16 PM Royce Taft via cctalk  >
> wrote:
>
> > That’s really disappointing to hear. I only discovered that museum for
> > myself via their website a couple of years ago and had no idea that it
> > closed. I had planned on visiting next time my wife and I travel to
> > Seattle.
> >
> > I hope that they are able to reopen.
> >
> > Royce
> >
> > Sent from my iPhone
> >
> > > On Oct 30, 2022, at 09:22, Michael Brutman via cctalk <
> > cctalk@classiccmp.org> wrote:
> > >
> > > My apologies if this topic is a sore point for some of you.  Their
> > abrupt
> > > closing wasn't that long ago.
> > >
> > > Does anybody have any insight on what is going on there?  The web site
> > has
> > > not been updated in about 2.5 years.  The world seems to be moving on;
> it
> > > would be nice to know if we're ever going to see the museum re-open,
> and
> > in
> > > what capacity.
> > >
> > > I realize the people are gone and scattered and it's never going to be
> > the
> > > same experience if it re-opens.  But there are plenty of us who still
> > > believe in the need for such a place, and starting from scratch would
> be
> > > difficult.
> > >
> > >
> > > -Mike
> > >
> > > (Off-list replies are welcomed if that makes the discussion easier ...)
> >
>

[cctalk] Re: Data General Nova and Eclipse Hobbyist License...

[Tom Hunter via cctalk]

Thank you Bruce! Thats great news.
Best regards
Tom

On Tue, 25 Oct 2022, 6:27 am Bruce Ray via cctalk, 
wrote:

>
> Wild Hare Computer Systems, Inc., is pleased to announce that a
> "Hobbyist License" is now available for legacy Data General
> Nova and Eclipse software.  This license allows educational, hobbyist,
> non-commercial use of the vast amount of DG software - software
> that changed the world in many ways.
>
> The initial archives are currently available at:
>
> www.NovasAreForever.org/dgsw
>
> and includes documentation for the corresponding software.
>
>
> This October announcement also honors the 54th anniversary of the original
> Data General Nova. An international celebration of the Nova's 50th
> anniversary was
> hosted by Wild Computer Systems in Colorado, USA.  Some of the festivities
> can be seen at:
>
> www.Nova-At-50.org
>
> and
>
> www.Nova-At-50.org/album/index.html
>
>
> To complement this Hobbyist License, a Nova and Eclipse emulator that
> can run all of the
> software will be introduced later this week.
>
>
> Wild Hare Computer Systems is dedicated to preserving Data General's
> significant contributions to computer history.  We seek DG hardware,
> software, documentation,
> sales literature - basically "anything DG" - that can be added to the
> archives for posterity.
>
>
>
> Bruce Ray
> Wild Hare Computer Systems, Inc.
> Denver, Colorado USA
> b...@wildharecomputers.com
>
> ...preserving the Data General legacy: www.NovasAreForever.org
>
> www.WildHareComputers.com
>
> www.NovasAreForever.org
>

[cctalk] Re: Bubble Memory

[Tom Hunter via cctalk]

I was not referring to you Jim. Your message was helpful unlike some of the
others.

On Sat, 22 Oct 2022, 12:39 pm Jim Brain via cctalk, 
wrote:

> On 10/21/2022 9:46 PM, Tom Hunter via cctalk wrote:
> > It would be better to stay on topic and avoid the hostile rhetoric of
> some
> > of the posts.
>
> Um, I am.  There were concerns about international shipping of this eBay
> item, followed by some info on eBay international shipping, so I was
> offering to help in general if folks need it, and noting that not
> everyone requires so much to ship.
>
> Jim
>
>

[cctalk] Re: Bubble Memory

[Tom Hunter via cctalk]

It would be better to stay on topic and avoid the hostile rhetoric of some
of the posts.
Thanks
Tom

On Sat, 22 Oct 2022, 9:49 am Jim Brain via cctalk, 
wrote:

> On 10/21/2022 4:55 AM, Peter Corlett via cctalk wrote:
> > On Fri, Oct 21, 2022 at 12:15:02PM +1100, Doug Jackson via cctalk wrote:
> > [...]
> >> Yet another American seler who doesn't understand how simple overseas
> >> shipping is.
> > As far as I can tell, the price to ship anything overseas from the USA is
> > twice the value of the item, plus fifty bucks, plus ten bucks per ounce.
> > Whether USPS actually charge this much or it's just sellers trying it
> on, I
> > neither know nor care.
> >
> > So I don't bother even looking at American sellers any more.
> >
> I ship all the time all over the world, and overseas shipping is a bit
> pricey, but I don't think it's quite that bad.  I think that's an eBay
> thing.
>
> I don't use PirateShip (though I am sure they are fine), as I have a
> business shipping manager I use, that gets me preferred rates like
> PirateShip.
>
> If you find something you'd like but the seller doesn't do
> international, feel free to reach out.  I'm not looking to make a
> business of reshipping, but I started this business to help folks enjoy
> their classic computing hobby, so I'm happy to help.
>
> As another posting noted, though, requests to modify customs forms is a
> problem.  The most vocal concerns I've heard are folks who buy outside
> the US, have t pay customs, and then complain to me that I should have
> shown the price of the item including customs and VAT and such costs. I
> agree it'd be nice, but it's untenable at times to pre-figure those fees.
>
> Jim
>
> --
>
> Jim Brain
> br...@jbrain.com
> www.jbrain.com
>

[cctalk] Re: Great Vintage Computer Heist of 2012

[Tom Hunter via cctalk]

Did you take them to court again to get compensation for what must have
been a substantial loss? Very strange story. You must have been furious.

On Mon, 17 Oct 2022, 4:54 pm Sellam Abraham via cctalk, <
cctalk@classiccmp.org> wrote:

> Long story very short:
>
> Landlords evicted me from their warehouse where my collection was stored
> and wouldn't let me back in.  Had to go to court.  Regained access and was
> able to pull out 20% of the collection before they locked me out again for
> good.  Then sold the rest to computer recyclers, who proceeded to scatter
> it to the wind.
>
> Sellam
>
> On Mon, Oct 17, 2022 at 1:43 AM Ali via cctalk 
> wrote:
>
> > You had to ask..I was there 3000 years ago (or about 10 years ago in
> > non Tolkien meme terms) and it wasn't pretty....
> >  Original message From: Tom Hunter via cctalk <
> > cctalk@classiccmp.org> Date: 10/17/22  1:31 AM  (GMT-08:00) To: "General
> > Discussion: On-Topic and Off-Topic Posts"  Cc:
> Tom
> > Hunter  Subject: [cctalk] Great Vintage Computer
> > Heist of 2012 Sellam Abraham referred to a "Great VintageComputer Heist
> of
> > 2012". What was that about? Who stole what and where andwhy?
>

[cctalk] Great Vintage Computer Heist of 2012

[Tom Hunter via cctalk]

Sellam Abraham referred to a "Great Vintage
Computer Heist of 2012". What was that about? Who stole what and where and
why?

[cctalk] Re: Philips P2000C carrying strap

[Tom Hunter via cctalk]

Check out this link for a detailed description of the "Stirling Cycle" in
particular the YouTube video at the bottom of the article is very well done
and shows a small machine in operation:

https://www.stirlingcryogenics.eu/en/the-stirling-cycle

Tom

On Sun, Oct 2, 2022 at 1:41 AM Paul Koning  wrote:

>
>
> > On Sep 30, 2022, at 11:19 PM, Tom Hunter  wrote:
> >
> > https://www.stirlingcryogenics.eu/
> >
> > These machines are still made and indeed are very cool.   ;-)
>
> So to speak!
>
> I didn't see their liquid helium machine.  I remember one installed at the
> TU Eindhoven physics department; it consisted of a pair of two-stage
> Stirling machines (which by themselves will liquify hydrogen or neon, i.e.,
> they go down to about 20 K) plus a bunch of auxiliary equipment.  The whole
> setup took maybe a 15 foot square room.
>
> The website doesn't show any of the compact machines I remember seeing
> described.  A bunch of those had 400 Hz power, indicating they were meant
> for airborne use.  One was a little lab bench machine, a box perhaps the
> size of an old style desktop PC, lying flat, with a "cold finger" sticking
> out of the box.
>
> paul
>
>

[cctalk] Re: Philips P2000C carrying strap

[Tom Hunter via cctalk]

https://www.stirlingcryogenics.eu/

These machines are still made and indeed are very cool.   ;-)

Tom

On Sat, Oct 1, 2022 at 4:54 AM Paul Koning via cctalk 
wrote:

>
>
> > On Sep 30, 2022, at 1:12 PM, Peter Corlett via cctalk <
> cctalk@classiccmp.org> wrote:
> >
> >> ...
> >
> > Note that there are (at least) _two_ Philips museums: the "Stichting tot
> > Behoud van Historische Philips Producten" (Foundation for the
> Preservation
> > of Historic Philips Products) and the Philips Museum. Their websites are
> > https://www.sbhp.nl/ and https://www.philips-museum.com/. Both are in
> > Eindhoven, as is much of the interesting bits of Philips itself.
> >
> > The former appears to be volunteer collectors of mainly analogue-era
> Philips
> > gear and I can almost smell the chain-smoked roll-ups just from the
> photos,
> > whereas the latter looks rather more corporate.
>
> It's hard to see what the significance of the latter is, if any.  The
> website has a "collection" tab that doesn't say anything about a
> collection.  The "eyecatchers" tab speaks of an exhibit of Philips
> advertising posters.  Ok, nice, but what does that have to do with the
> technology and products and enormous R contribution of the company?
>
> The former at least shows something about the collection, a set of nice
> photos of stuff.  That and a hint that there is more -- but no description
> of what that might be.
>
> I keep wondering if anything whatsoever about the PR8000 has been
> preserved anywhere.  I have a marketing brochure that I scanned and sent to
> Bitsavers, plus some notes about the parts of the instruction set that show
> up in a program of mine.  But I've never seen anything else, even finding
> any mention of the machine is nearly impossible.
>
> I still regret I didn't save the Stirling cryogenic machine brochures I
> had as a teenager -- neat machines Philips built for easily and cheaply
> making lab quantities of liquid nitrogen and even liquid helium.  Some were
> backpack size, apparently for airborne applications.  I also had a brochure
> of their neutron generator tube, which is a pretty wild device.
>
> paul
>
>
>

[cctalk] Timeline of Computer History

[Tom Hunter via cctalk]

I have just stumbled across this nice "Timeline of Computer History" from
the CHM:

https://www.computerhistory.org/timeline/computers/

I have not seen this before and thought it may be of interest to this list.

Tom

[cctalk] Re: Minicomputer front panel.

[Tom Hunter via cctalk]

Adrian's find is true computer archaeology.
It will be fit for a museum of 20th century computing ... in 1000 years.
;-)


On Sun, Sep 25, 2022 at 9:42 PM Adrian Stoness via cctalk <
cctalk@classiccmp.org> wrote:

> yea was found in the mud the press board preic spent a few yrs outside
> after i found the first bits yet it survived had put it under some weight
> for few weeks to get rid of the curve it had
>
> https://live.staticflickr.com/4159/34433937071_ddcbdb994a_b.jpg
>
> On Sat, Sep 24, 2022 at 11:24 PM Sellam Abraham via cctalk <
> cctalk@classiccmp.org> wrote:
>
> > Rebuild as in Steve Austin.  Holy crap.
> >
> > Sellam
> >
> > On Sat, Sep 24, 2022 at 8:29 PM Adrian Stoness via cctalk <
> > cctalk@classiccmp.org> wrote:
> >
> > > ive got a 8i i need to finish rebuilding
> > >
> > >
> >
> https://www.flickr.com/photos/1ajs/34539786085/in/photolist-UsNVQc-UnZy3U-UnXoiN-UCar4c-Tj2Q4F-svoMkx-rRe2wa-sMGsvE-snF3C3-snMK88-snF3G1-sqYYGV-sr1sL2-shWVmZ-seqzS6-rhEMQD-rhtjmd-sdACea-Mfq4ar-KhqDsy
> > >
> > >
> > >
> > > On Sat, Sep 24, 2022 at 8:36 PM jim stephens via cctalk <
> > > cctalk@classiccmp.org> wrote:
> > >
> > > >
> > > >
> > > > On 9/24/22 14:59, Adrian Stoness via cctalk wrote:
> > > > > o?
> > > > >
> > > > > On Sat, Sep 24, 2022 at 12:30 PM jos via cctalk <
> > cctalk@classiccmp.org
> > > >
> > > > > wrote:
> > > > >
> > > > >> On 24.09.22 04:57, Adrian Stoness via cctalk wrote:
> > > > >>> Wow someone mentioning à phillips p series
> > > > >>> Has a p854 new old stock panel my self along with bunch of
> manuals
> > > and
> > > > à
> > > > >>> spare core memory pack in safe keeping
> > > > >>
> > > > >> I have spare P854's.
> > > > >>
> > > > >> Jos
> > > > >>
> > > > >>
> > > > There is Oscar's actual computers, a PDP 11 replica and PDP8 replica
> as
> > > > well as great IMSAI and Altairs available which look great as well as
> > > > being actual simulators or emulators of the computers, with the
> > lights,
> > > > not just dead displays.
> > > >
> > > > For display, on could get front panels from Ron Smallwood and produce
> > > > switches and the other few parts required by 3d printing and make a
> > > > pretty good display panel.
> > > >
> > > > thanks
> > > > Jim
> > > >
> > >
> >
>

[cctalk] Re: Minicomputer front panel.

[Tom Hunter via cctalk]

Of course I meant disk platters in working configuration as in disk packs
or stacks of platters on a spindle, not loose platers extracted from packs
or stacks and converted into coffee tables or wall ornaments.:-)

Tom

On Fri, Sep 23, 2022 at 9:09 PM Paul Koning  wrote:

>
>
> > On Sep 22, 2022, at 10:44 PM, Tom Hunter via cctalk <
> cctalk@classiccmp.org> wrote:
> >
> > I cannot understand the mindset of people who buy up components
> desperately
> > sought by others who want to restore machines just to nail them to their
> > man cave or living room wall.
> > These same types of people vacuum up core memory boards, keyboards, disk
> > platters, 9-track tapes, etc just for bragging rights and as a result
> > depriving those who restore and preserve computer systems from doing so.
>
> Agreed for the most part, with the exception of disk platters.  While it
> might be theoretically possible to repair a disk pack, or disk drive, given
> a loose platter in good condition, I doubt this is practical.  Partly
> because few if any of us have the precision equipment needed to do this,
> and partly because loose platters are typically loose because they were
> wrecked.
>
> There might be some exceptions: a spare RF11 or RC11/RS64 platter merely
> needs to be bolted to the spindle hub and formatted, that's a normal field
> repair procedure.  But, say, a platter out of an RP04 pack is unlikely ever
> to be able to serve as anything more than a wall hanging or a prop.
>
> paul
>
>

[cctalk] Re: Minicomputer front panel.

[Tom Hunter via cctalk]

I cannot understand the mindset of people who buy up components desperately
sought by others who want to restore machines just to nail them to their
man cave or living room wall.
These same types of people vacuum up core memory boards, keyboards, disk
platters, 9-track tapes, etc just for bragging rights and as a result
depriving those who restore and preserve computer systems from doing so.
For some time I have been looking for a PDP-8/e front panel PCB needed to
make a machine complete. Until now I had no luck. No doubt there are dozens
of these hanging off people's walls.
Like Peter I don't care if the PCB is functional, but unlike Peter I can
and will repair it.
Peter please consider the negative impact of your hobby on historically
valuable computer systems.
Tom


On Fri, Sep 23, 2022 at 1:33 AM Peter Van Peborgh via cctalk <
cctalk@classiccmp.org> wrote:

> I know this is sacrilege but I am looking for the front panel of a *Data
> General Nova *and/or *a DEC PDP 8/11/12/15*.
> Why? I collect artefacts from the days of the minicomputer and earlier and
> I want them for my collection/display. They should be not too damaged and
> of course do not need to be functional. I would be willing to pay
> postage/freight.
> Any offers? Any offers?
> Peter
>
> PS Please don't shout at me!
>

[cctalk] Re: 7485 chip history??? (Solid State Music SB-1)

[Tom Hunter via cctalk]

And I thought shipping to Australia (opposite side of the planet) was
expensive.
Shipping from the US to Canada should be dirt cheap as mail can move via
trains not air freight.
$75 shipping for an IC is crazy no matter what the destination is (except
maybe Mars).

Tom

On Tue, Sep 20, 2022 at 12:51 PM ben via cctalk 
wrote:

> On 2022-09-19 10:18 p.m., Tom Hunter via cctalk wrote:
> > There are a few US based Ebay sellers of the 74L85.
> >
> > Tom
> But most ebay sellers, from the USA seem to sell a item for $6.00 and
> $75 shipping to Canada. China $2 and $3 shipping. With Covid all
> shipping is several weeks.
> Ben.
>
>
>
>

[cctalk] Re: 7485 chip history??? (Solid State Music SB-1)

[Tom Hunter via cctalk]

There are a few US based Ebay sellers of the 74L85.

Tom

On Tue, Sep 20, 2022 at 10:50 AM ben via cctalk 
wrote:

> On 2022-09-19 8:07 p.m., William Sudbrink via cctalk wrote:
> > Hi,
> >
> > I recently acquired a Solid State Music SB-1 from which all the chips had
> > been removed.  I've reinstalled all of the chips (I located an SSM2000)
> and
> > I've been trying to figure out why this board crashes my computers.  The
> > conclusion that I've come to is rather astounding.  The board specifies
> two
> > 74ls85 4 bit binary comparator chips to perform address decoding.  The
> > designers of this board seem to have had incorrect pinouts for it.  Every
> > source that I can find specifies:
> >
> >B3116 VCC
> > A > A=B (in)3 14 B2
> > A>B (in)4 13 A2
> > A>B (out) 5 12 A1
> > A=B (out) 6 11 B1
> > A >   GND 8  9 B0
> >
> > The 7485s that I was able to get have this pinout.  BUT!  The SB-1 is
> > designed as:
> >
> >B2   1 16 VCC
> >A2   2 15 A3
> > A=B (out) 3 14 B3
> > A>B (in)4 13 A>B (out)
> > A > A=B (in)6 11 B0
> >A1   7 10 A0
> >GND8  9 B1
> >
> > I Ohm'd out the board to verify this and it matches the schematic here:
> > https://wiki.theretrowagon.com/wiki/Solid_State_Music_SB1
> > What the heck???  Did the pinout of the 7485 just arbitrarily change at
> some
> > point?  Was this some competition between manufacturers?  Is there any
> way
> > to get the "right" 7485?
> >
> They are both right.
> 7485,74LS85,74S85 top pin out.
> 74L85 the bottom pin out. SB-1
> TTL data book 1985.
> >
> > Thanks,
> > Bill
> >
> >
> I suspect they used the L for low input loading
>   for the address bus. The 74C85 (fairchild ) would be the sane
> substitute for the 74L85.
> Ben.
>
>

[cctalk] Re: [cctalk]Can someone explain...

[Tom Hunter via cctalk]

Ebay madness.

On Mon, 18 Jul 2022, 10:57 pm William Sudbrink via cctalk, <
cctalk@classiccmp.org> wrote:

> Why anybody would bid more than three hundred dollars for a bunch of ribbon
> cables?
>
>
>
>
> https://www.ebay.com/itm/234623364778?hash=item36a0a46eaa:g:y1oAAOSwwQdiz550
>
>
>
> Unless there's something I'm not seeing here, I can easily (and exactly)
> reproduce them.
>
> I could even make them with red or "rainbow" cables if you prefer.  I'll do
> a set for the
>
> "bargain" price of $250.
>
>
>
> Bill S.
>
>
>
> --
> This email has been checked for viruses by Avast antivirus software.
> https://www.avast.com/antivirus
>

Re: Cctalk subscription disabled

[Tom Hunter via cctalk]

Strangely I did not receive jwest's reply quoted by Anders Nelson in my
Gmail account.
It is quoted in Anders' email and I see the original message from jwest in
the cctalk archive.
My Gmail Spam folder is empty.
What is going on?
It is as if classiccmp.org is blacklisted by Gmail.

Tom Hunter

On Wed, May 11, 2022 at 11:09 PM Anders Nelson 
wrote:

> Yes I've been getting the same "excessive bounces" emails as well!
> --
> Anders Nelson
>
> +1 (517) 775-6129
>
> www.erogear.com
>
>
> On Wed, May 11, 2022 at 8:17 AM jwest--- via cctalk 
> wrote:
>
>> Yes, Adrian is correct – known for some time but my time/focus has been
>> elsewhere. Addressed yesterday, should make gmail less fussy.
>>
>>
>>
>> J
>>
>>
>>
>> From: cctalk  On Behalf Of Tom Hunter
>> Sent: Wednesday, May 11, 2022 7:06 AM
>> To: Adrian Stoness ; cctalk-ow...@classiccmp.org
>> Cc: General Discussion: On-Topic and Off-Topic Posts <
>> cctalk@classiccmp.org>
>> Subject: Re: Cctalk subscription disabled
>>
>>
>>
>> I wonder if this problem is related to DMARC anti-spam.
>>
>> Maybe the following would help the list admin:
>>
>>
>>
>> https://wiki.list.org/DEV/DMARC
>>
>> https://dmarc.org/wiki/FAQ
>>
>>
>>
>> Thanks
>>
>> Tom
>>
>>
>>
>> On Wed, May 11, 2022 at 2:26 PM Adrian Stoness > <mailto:tdk.kni...@gmail.com> > wrote:
>>
>> gmail is causing it
>>
>>
>>
>> On Wed, May 11, 2022 at 1:15 AM Tom Hunter via cctalk <
>> cctalk@classiccmp.org <mailto:cctalk@classiccmp.org> > wrote:
>>
>> I didn't receive any cctalk messages for a few days, so I checked my Spam
>> folder (empty) and then the archive which had several new messages I
>> haven't seen. I then checked my cctalk membership configuration.
>> Surprisingly "Mail delivery" was disabled.
>>
>> Some time ago I received a few emails from the list server about
>> "excessive
>> bounces" saying that I should simply reply to the email otherwise my
>> subscription would be disabled. I replied and didn't think too much about
>> it. This time I got no "excessive bounces" email but my subscription got
>> disabled.
>>
>> I got an otherwise reliable @gmail.com <http://gmail.com>  email
>> address. Does anyone else here
>> have problems with this? Is there some way of preventing this from
>> happening?
>>
>> Thanks
>> Tom
>>
>>

Re: Cctalk subscription disabled

[Tom Hunter via cctalk]

I wonder if this problem is related to DMARC anti-spam.
Maybe the following would help the list admin:

https://wiki.list.org/DEV/DMARC
https://dmarc.org/wiki/FAQ

Thanks
Tom

On Wed, May 11, 2022 at 2:26 PM Adrian Stoness  wrote:

> gmail is causing it
>
> On Wed, May 11, 2022 at 1:15 AM Tom Hunter via cctalk <
> cctalk@classiccmp.org> wrote:
>
>> I didn't receive any cctalk messages for a few days, so I checked my Spam
>> folder (empty) and then the archive which had several new messages I
>> haven't seen. I then checked my cctalk membership configuration.
>> Surprisingly "Mail delivery" was disabled.
>>
>> Some time ago I received a few emails from the list server about
>> "excessive
>> bounces" saying that I should simply reply to the email otherwise my
>> subscription would be disabled. I replied and didn't think too much about
>> it. This time I got no "excessive bounces" email but my subscription got
>> disabled.
>>
>> I got an otherwise reliable @gmail.com email address. Does anyone else
>> here
>> have problems with this? Is there some way of preventing this from
>> happening?
>>
>> Thanks
>> Tom
>>
>

Re: Cctalk subscription disabled

[Tom Hunter via cctalk]

Gmail is by far the biggest email provider and works fine with other
Mailman based mailing lists.
How exactly is Gmail causing it and what is the work-around?

Thanks
Tom

On Wed, May 11, 2022 at 2:26 PM Adrian Stoness  wrote:

> gmail is causing it
>
> On Wed, May 11, 2022 at 1:15 AM Tom Hunter via cctalk <
> cctalk@classiccmp.org> wrote:
>
>> I didn't receive any cctalk messages for a few days, so I checked my Spam
>> folder (empty) and then the archive which had several new messages I
>> haven't seen. I then checked my cctalk membership configuration.
>> Surprisingly "Mail delivery" was disabled.
>>
>> Some time ago I received a few emails from the list server about
>> "excessive
>> bounces" saying that I should simply reply to the email otherwise my
>> subscription would be disabled. I replied and didn't think too much about
>> it. This time I got no "excessive bounces" email but my subscription got
>> disabled.
>>
>> I got an otherwise reliable @gmail.com email address. Does anyone else
>> here
>> have problems with this? Is there some way of preventing this from
>> happening?
>>
>> Thanks
>> Tom
>>
>

Cctalk subscription disabled

[Tom Hunter via cctalk]

I didn't receive any cctalk messages for a few days, so I checked my Spam
folder (empty) and then the archive which had several new messages I
haven't seen. I then checked my cctalk membership configuration.
Surprisingly "Mail delivery" was disabled.

Some time ago I received a few emails from the list server about "excessive
bounces" saying that I should simply reply to the email otherwise my
subscription would be disabled. I replied and didn't think too much about
it. This time I got no "excessive bounces" email but my subscription got
disabled.

I got an otherwise reliable @gmail.com email address. Does anyone else here
have problems with this? Is there some way of preventing this from
happening?

Thanks
Tom

Re: Repairing a VT240.

[Tom Hunter via cctalk]

You misunderstood what I wrote.
I just expressed surprise about the cost rather than criticizing your
choice of thermal camera.
Other brands are expensive too.
I wonder what makes these cameras more expensive than ordinary USB cameras
working in the visible spectrum.


On Mon, May 2, 2022 at 8:26 PM Chris Zach  wrote:

> Feel free to recommend a better one. I repair electronics in my spare
> time, and it has paid for itself many times over.
>
> C
>
> On 5/1/2022 11:59 PM, Tom Hunter wrote:
> > The Seek Thermal is surprisingly expensive for what it is - a USB camera
> > working in the infrared spectrum.
> >
> >
> > On Mon, May 2, 2022 at 12:19 AM Chris Zach via cctalk
> > mailto:cctalk@classiccmp.org>> wrote:
> >
> > On 5/1/2022 2:14 AM, Rob Jarratt wrote:
> >  > That's interesting. What did you use for the thermal camera?
> >
> > Seek Thermal connected to a Samsung Galaxy 6 Note. Works pretty well
> to
> > spot hot components. I look for the relative temp differences, a
> bright
> > red spot on a particular chip is something to investigate.
> >
>

Re: Repairing a VT240.

[Tom Hunter via cctalk]

The Seek Thermal is surprisingly expensive for what it is - a USB camera
working in the infrared spectrum.


On Mon, May 2, 2022 at 12:19 AM Chris Zach via cctalk 
wrote:

> On 5/1/2022 2:14 AM, Rob Jarratt wrote:
> > That's interesting. What did you use for the thermal camera?
>
> Seek Thermal connected to a Samsung Galaxy 6 Note. Works pretty well to
> spot hot components. I look for the relative temp differences, a bright
> red spot on a particular chip is something to investigate.
>

Re: BASIC environment ending with "run complete", and slashed 'O' characters?

[Tom Hunter via cctalk]

Yes - CDC 6000 and CYBER series machines running BASIC 2.1 (and all later
versions) under KRONOS and NOS output "RUN COMPLETE." when the user program
finished.

Tom

On Tue, Apr 26, 2022 at 7:29 PM Jules Richardson via cctalk <
cctalk@classiccmp.org> wrote:

> On 4/26/22 02:05, Raymond Wiker wrote:
> > https://en.wikipedia.org/wiki/CDC_Kronos
> > , perhaps?
>
> Could well be, given the MECC / Minnesota / Cray connections. Question
> then
> is whether the CDC 6000 series (or later) machines had a BASIC environment
> that terminated runs with the 'run complete' message.
>
> (oddly I never saw my post make it to the list, so assumed it was down or
> the message had got caught somewhere. Evidently it did make it though and
> for some reason my 'list copy' of it never made it back to me)
>
> Jules
>

Re: PCI floppy controller

[Tom Hunter via cctalk]

I am curious about your comment about "kryoflux going south".
I did not hear about any problems. Could you please elaborate?
I got mine about 2 or 3 years ago and it did everything I needed at the
time, but haven't used it since.

Thanks
Tom


On Sat, Apr 23, 2022 at 9:19 AM Warner Losh via cctalk <
cctalk@classiccmp.org> wrote:

> On Fri, Apr 22, 2022 at 7:07 PM Bill Gunshannon via cctalk <
> cctalk@classiccmp.org> wrote:
>
> >
> > As another person with a desire to be able to read/write/create
> > disks of different sizes and formats I have found this interesting.
> >
> > So the question, then
> >
> > How hard would it be to make a floppy disk interface using an Arduino
> > or even RasberryPi?  If you could do that the choices of interface
> > to a PC opens up quite a bit.  It would never be like having a floppy
> > hanging off the PC, but then none of the formats I am interested in
> > are grounded in the PC anyway and utilities would need to be written
> > to access them.
> >
> > comments?
> >
>
> Isn't that what Greaseweasel  and similar do? I have a kyroflux that I use
> to read floppies on my macbook. It can write as well and understands a ton
> of formats. Greaseweasel is more available and supported (I got my kyroflux
> before things went south, so wouldn't recommend others get one these
> days).
>
> Warner
>

Re: Core memory

[Tom Hunter via cctalk]

DEC PDP-8/e core memories have a combined Sense/Inhibit line.
There are only 3 wires through each core donut: X, Y, Sense/Inhibit.
The PDP-8/e core memory is very well described starting at page 3-60 of the
Maintenance Manual Volume 1:

http://www.bitsavers.org/pdf/dec/pdp8/pdp8e/DEC-8E-HMM1A-D-D_PDP-8e_Maintenance_Manual_Volume_1_Processor_Sep73.pdf

Tom Hunter

On Sun, Apr 3, 2022 at 7:04 AM Curious Marc via cctalk <
cctalk@classiccmp.org> wrote:

> You don’t strictly need an inhibit wire to write cores. You can write the
> core with just the addressing lines. The inhibit wire is just there to
> simplify the addressing electronics logic in early core memory, so you
> don’t need to have per core control of the current in the address lines
> when writing. You just do it wholesale: scan all address lines with current
> in one direction during reads, scan once again with current in the other
> direction during writes, with inhibit when needed.
>
> You could certainly use the sense wire as an inhibit. But that gets
> impractical with a diagonal weave, because you’d have to know in which
> direction the inhibit works and reverse the inhibit current accordingly.
> And it’s different for each core depending on the direction the sense wire
> crosses the core. So it defeats the purpose of simplifying the control
> logic with an inhibit wire. Therefore I don’t think that scheme is used.
>
> In practice, 3 wire systems that use the same wire for inhibit and sense
> (like some IBM core planes) have the sense go along the address lines, and
> use a half plane column shift to provide cancellation of the unwanted
> signal induced from the address line it is running along. We demonstrate
> such a 3 wire plane here: https://youtu.be/AwsInQLmjXc .
>
> So in your plane, the sense wire is likely just used for reads, and the
> writes are done uniquely with the address wires, like I demonstrate here:
> https://youtu.be/7ozNMgx7WtQ
>
> Marc
>
> > On Apr 1, 2022, at 2:14 PM, Brent Hilpert via cctalk <
> cctalk@classiccmp.org> wrote:
> >
> > On 2022-Apr-01, at 11:51 AM, Paul Koning wrote:
>  On Apr 1, 2022, at 2:38 PM, Brent Hilpert via cctalk <
> cctalk@classiccmp.org> wrote:
>  On 2022-Apr-01, at 6:02 AM, Paul Koning via cctalk wrote:
> >>>
>  When I looked at that ebay listing of "glass memory" it pointed me to
> another item,https://www.ebay.com/itm/265623663142 -- described as "core
> rope memory".  Obviously it isn't -- it's conventional core RAM.
> Interestingly enough, it seems to be three-wire memory (no inhibit line
> that I can see).  It looks to be in decent shape.  No manufacturer marks,
> and "GC-6" doesn't ring any bells.
> >>>
> >>> Well, it would still work for 1-bit-wide words, so to speak. One
> wonders what the application was.
> >>
> >> I wonder if the sense wire was used as inhibit during write cycles --
> that seems doable.  It would make the core plane simpler at the expense of
> more complex electronics.  With that approach, you have regular memory, not
> limited to 1 bit words.
> >
> > Maybe I'm being overly cautious, but offhand I'm initially skeptical
> without doing the math or some good vector diagrams, or seeing an example.
> With the diagonal wire you're changing the current/magnetic sum vectors in
> direction and magnitude. The question is coming up with a current that
> reliably performs the cancellation function on the selected core of a
> bit-array while reliably *not* selecting another core, while accounting for
> all the variation tolerances in the array.
> >
> > While there's probably some value by which it would work in theory, I
> wonder whether the diagonal wire would narrow the operating margins. From
> some stuff I've seen, the hysteresis curves for cores weren't spectacularly
> square. With the usual 3D-3wire scheme of a close parallel inhibit wire you
> have 'cancellation by simplicity', you maximise the difference
> (cancellation) influence on one wire while minimising it's sum influence on
> the other.
> >
> > A related issue is the normal diagonal sense stringing (which this looks
> to have) has the wire entering the cores from both directions relative to
> the address wires, which is why sense amplifiers respond to pulses of both
> polarity. If this diagonal wire is put to use as an inhibit wire, some
> logic is needed to decide the direction of the inhibit current from the
> address, though that may not be very difficult.
> >
> > Some history of the 3-wire development might tell, whether inhibit was
> first applied to a diagonal sense stringing or whether sense was first
> applied to an adapted parallel-inhibit stringing. The real benefit of the
> 3-wire development was getting rid of the diagonal stringing for
> manufacturing ease.
> >
> >
> >>> There are a couple of Soviet core-rope memories up right now:
> >>>https://www.ebay.com/itm/294558261336
> >>>https://www.ebay.com/itm/294851032351
> >>
> >> Neat looking stuff.  It doesn't look like core rope 

Re: Searching cctalk archives?

[Tom Hunter via cctalk]

Thank you Jim and Pbirkel for your help.

Sorry for the slow reply. I live on the west coast of Australia in Perth
(GMT+8) so our time zones differ a lot.

Best regards
Tom Hunter

On Wed, Mar 23, 2022 at 11:25 AM jim stephens via cctalk <
cctalk@classiccmp.org> wrote:

> sorry to put on list, but never heard from Tom about what I sent him.
> thanks
> Jim
>
> On 3/22/2022 9:23 AM, Tom Hunter via cctalk wrote:
> > I came across a reference to a cctalk message from 9 September 200
>
>

Searching cctalk archives?

[Tom Hunter via cctalk]

I came across a reference to a cctalk message from 9 September 2006 and
would like to read the rest of the thread with the subject "PDP-8m Console
Switch Problems - fixed!".

Unfortunately it appears that the cctalk archive does not go back to 2006.

Is there some place with the complete cctalk archive or at least back to
Sept 2006?

I have also been trying to search the cctalk archive, but short of
downloading every month and unzip it, there appears to be no easy way of
searching. What do experienced cctalk members do?

Thanks
Tom Hunter

Re: LSSM is chasing this, was Re: General Data? Computer Equipment Auction - GSA

[Tom Hunter via cctalk]

Dave,

Your following comment is offensive:

"I hope these systems go to a good home, and don't disappear into the black
hole of a private collection."

You equate private collections with black holes. I think on the contrary
many private collectors do a better job at preserving old systems than
"museums".

I remember several "museums" which have failed in recent years.
At least four of them have been much too greedy and took on way more than
they could handle and in effect turned the collections into scrap.

And then there is of course the sorry saga of the Living Computer "Museum"
in Seattle which has sucked up a lot of old systems from private collectors.



On Thu, Mar 17, 2022 at 6:05 AM Dave McGuire via cctalk <
cctalk@classiccmp.org> wrote:

> On 3/16/22 16:56, Dave McGuire via cctalk wrote:
> >> The LSSM is very interested in this machine for public display.  It
> would
> >> complement the museum's collection of PDP-11s and other 16 bit machines.
> >
> >By "very interested", Mark means "is actively pursuing".  Some of our
> > donors are willing to foot the bill for the acquisition and subsequent
> > retrieval trip; we've just about got it covered.
> >
> >For those who may be unaware, LSSM is a public minicomputer/mainframe
> > museum in Pittsburgh, a registered 501(c)(3) nonprofit organization,
> > that has been open for about six years.  The two DG machines in this
> > auction will have a good home with us; it is our intention to restore
> > them and place them on public exhibit for use.  We have an established
> > track record of "getting the job done" in this context.
> >
> >I'm letting this crowd know in case any of the current bidders are
> > here and just trying to keep these machines out of the scrap stream,
> > etc.  We are donor-funded and don't have a lot to spend on this.
> >
> >If you would like to support us in this endeavor, we accept donations
> > by check or via PayPal, see http://www.lssmuseum.org for more
> > information.  Donations may be tax-deductible depending on your personal
> > tax situation.
> >
> >Thank you for your consideration.
>
>Ok, it hit $1200, we're out of the running.  I hope these systems go
> to a good home, and don't disappear into the black hole of a private
> collection.
>
>  -Dave
>
> --
> Dave McGuire, AK4HZ
> New Kensington, PA
>

Re: cctalk Digest, Vol 90, Issue 7 - Re: DEC H500 Digital Computer Lab

[Tom Hunter via cctalk]

Hi Gerhard,

The Farnell plugs seem to be 2 mm not 0.1".
I suspect the Pomona plugs you mentioned earlier will be a better fit.
You need at least 100 leads which means at least 200 plugs.
I would get samples of both types before committing to a larger purchase.

Best regards
Tom

On Mon, Mar 14, 2022 at 4:55 PM DI Gerhard Kreuzer <
gerhard.kreu...@liftoff.at> wrote:

> Hi Tom,
>
> here another source/manufacture ..
>
> 2550327.pdf (farnell.com) 
>
> With best regards
>
> Gerhard
>
> Zitat von Tom Hunter :
>
> Hi Gerhard,
>
> Yes - these look good but the price is much higher than what I paid. As I
> no longer work, modifying the cheap Chinese banana plugs was viable. If you
> still work and are time limited then the Pomona plugs may be the better
> option. It may be best to get a small number first to try before committing
> to a larger order.
>
> Best regards
> Tom
>
>
>
>
> On Mon, Mar 14, 2022 at 1:06 AM DI Gerhard Kreuzer <
> gerhard.kreu...@liftoff.at> wrote:
>
>> Hi Tom,
>>
>> what do you think about this parts:
>>
>> Microsoft Word - D5936.doc (mouser.at)
>> 
>>
>> Looks like 0.09" diameter.
>>
>> With best regards
>>
>> Gerhard
>>
>> Zitat von Tom Hunter :
>>
>> Hi Gerhard,
>>
>> I used the following banana plugs:
>>
>> https://www.aliexpress.com/item/1005002907717547.html
>>
>> Please note that only about 30% of the plugs I received were a good fit.
>> The rest I had to modify.
>>
>> I had to remove the barrel shaped contact spring and compress it
>> carefully to open it up to make good contact with the sockets.
>> I also soldered the barrel shaped contact spring onto the plug body. It
>> is a lot of work to make the patch cables with plugs which don't quite fit,
>> but with the modification the result is now neat and usable.
>>
>> I couldn't find anything else with a better fit. The original 0.1" taper
>> pins are "unobtainium".
>>
>> Regards
>> Tom
>>
>>
>>
>> On Sun, Mar 13, 2022 at 7:18 PM DI Gerhard Kreuzer via cctalk <
>> cctalk@classiccmp.org> wrote:
>>
>>> Hi,
>>> I also have an H500 waiting for restoration.
>>> Maybe anyone can give better winfos about the plugs/connectors of the
>>> patch cables.
>>>
>>> I didn't have any, I have to make new.
>>>
>>> With best regards
>>>
>>> Gerhard
>>>
>>> Zitat von cctalk-requ...@classiccmp.org:
>>> > Send cctalk mailing list submissions to
>>> >   cctalk@classiccmp.org
>>> >
>>> >   To subscribe or unsubscribe via the World Wide Web, visit
>>> >   http://www.classiccmp.org/mailman/listinfo/cctalk
>>> >   or, via email, send a message with subject or body 'help' to
>>> >   cctalk-requ...@classiccmp.org
>>> >
>>> >   You can reach the person managing the list at
>>> >   cctalk-ow...@classiccmp.org
>>> >
>>> >   When replying, please edit your Subject line so it is more
>>> > specificthan "Re: Contents of cctalk digest..."
>>>
>>
>>
>>
>
>
>

Re: cctalk Digest, Vol 90, Issue 7 - Re: DEC H500 Digital Computer Lab

[Tom Hunter via cctalk]

Hi Gerhard,

Yes - these look good but the price is much higher than what I paid. As I
no longer work, modifying the cheap Chinese banana plugs was viable. If you
still work and are time limited then the Pomona plugs may be the better
option. It may be best to get a small number first to try before committing
to a larger order.

Best regards
Tom



On Mon, Mar 14, 2022 at 1:06 AM DI Gerhard Kreuzer <
gerhard.kreu...@liftoff.at> wrote:

> Hi Tom,
>
> what do you think about this parts:
>
> Microsoft Word - D5936.doc (mouser.at)
> 
>
> Looks like 0.09" diameter.
>
> With best regards
>
> Gerhard
>
> Zitat von Tom Hunter :
>
> Hi Gerhard,
>
> I used the following banana plugs:
>
> https://www.aliexpress.com/item/1005002907717547.html
>
> Please note that only about 30% of the plugs I received were a good fit.
> The rest I had to modify.
>
> I had to remove the barrel shaped contact spring and compress it carefully
> to open it up to make good contact with the sockets.
> I also soldered the barrel shaped contact spring onto the plug body. It is
> a lot of work to make the patch cables with plugs which don't quite fit,
> but with the modification the result is now neat and usable.
>
> I couldn't find anything else with a better fit. The original 0.1" taper
> pins are "unobtainium".
>
> Regards
> Tom
>
>
>
> On Sun, Mar 13, 2022 at 7:18 PM DI Gerhard Kreuzer via cctalk <
> cctalk@classiccmp.org> wrote:
>
>> Hi,
>> I also have an H500 waiting for restoration.
>> Maybe anyone can give better winfos about the plugs/connectors of the
>> patch cables.
>>
>> I didn't have any, I have to make new.
>>
>> With best regards
>>
>> Gerhard
>>
>> Zitat von cctalk-requ...@classiccmp.org:
>> > Send cctalk mailing list submissions to
>> >   cctalk@classiccmp.org
>> >
>> >   To subscribe or unsubscribe via the World Wide Web, visit
>> >   http://www.classiccmp.org/mailman/listinfo/cctalk
>> >   or, via email, send a message with subject or body 'help' to
>> >   cctalk-requ...@classiccmp.org
>> >
>> >   You can reach the person managing the list at
>> >   cctalk-ow...@classiccmp.org
>> >
>> >   When replying, please edit your Subject line so it is more
>> > specificthan "Re: Contents of cctalk digest..."
>>
>
>
>

Re: cctalk Digest, Vol 90, Issue 7 - Re: DEC H500 Digital Computer Lab

[Tom Hunter via cctalk]

Hi Gerhard,

I used the following banana plugs:

https://www.aliexpress.com/item/1005002907717547.html

Please note that only about 30% of the plugs I received were a good fit.
The rest I had to modify.

I had to remove the barrel shaped contact spring and compress it carefully
to open it up to make good contact with the sockets.
I also soldered the barrel shaped contact spring onto the plug body. It is
a lot of work to make the patch cables with plugs which don't quite fit,
but with the modification the result is now neat and usable.

I couldn't find anything else with a better fit. The original 0.1" taper
pins are "unobtainium".

Regards
Tom


On Sun, Mar 13, 2022 at 7:18 PM DI Gerhard Kreuzer via cctalk <
cctalk@classiccmp.org> wrote:

> Hi,
> I also have an H500 waiting for restoration.
> Maybe anyone can give better winfos about the plugs/connectors of the
> patch cables.
>
> I didn't have any, I have to make new.
>
> With best regards
>
> Gerhard
>
> Zitat von cctalk-requ...@classiccmp.org:
> > Send cctalk mailing list submissions to
> >   cctalk@classiccmp.org
> >
> >   To subscribe or unsubscribe via the World Wide Web, visit
> >   http://www.classiccmp.org/mailman/listinfo/cctalk
> >   or, via email, send a message with subject or body 'help' to
> >   cctalk-requ...@classiccmp.org
> >
> >   You can reach the person managing the list at
> >   cctalk-ow...@classiccmp.org
> >
> >   When replying, please edit your Subject line so it is more
> > specificthan "Re: Contents of cctalk digest..."
>

Re: DECmate II disk image tooling?

[Tom Hunter via cctalk]

David,
I have a working DECmate III I could try your images on.
Tom

On Sun, 13 Mar 2022, 4:20 am David Schmidt via cctech, <
cct...@classiccmp.org> wrote:

> I have some disks that look like they're from a DECmate II computer,
> standard RX50K drives.  The disk images all look like they're a mix of
> 12-bit (OS/78 or OS/278?) and 8-bit all on the same media.  I can't
> convince PUTR to make sense of the images, so I'm wondering if there is
> anything else out there that is likely to be able to examine the disk
> contents?  I'm really looking for PUTR-like functionality to list and copy
> files.
>
> Maybe SIMH could be configured to be a DECmate II and be fed the disks?
>
> I have a couple of disk images available in case anyone wants to try them
> out - they're purported to be "DECmate II CP/M 2.2 version 2.0" and "System
> Disk ver. 2.0 8/24/87":
>
> https://drive.google.com/drive/folders/1PD0TlUPiT7MIPEX6abEn33e7s3kSXp_H?usp=sharing
>
> - David
>

Re: General Data? Computer Equipment Auction - GSA

[Tom Hunter via cctalk]

The rack on the left has a DG NOVA 2 and the rack on the right may be a DG
NOVA 1200. Sadly I am in Australia so shipping is prohibitively expensive.
Hopefully these systems find a good new home.
Tom

On Sun, 13 Mar 2022, 8:27 am Nigel Johnson Ham via cctalk, <
cctalk@classiccmp.org> wrote:

> Looks more like Data General to me with that blue livery
>
> Nigel Johnson, MSc., MIEEE, MCSE VE3ID/G4AJQ/VA3MCU
> Amateur Radio, the origin of the open-source concept!
> Skype:  TILBURY2591
>
>
> On 2022-03-12 19:10, STAN IRWIN via cctalk wrote:
> > Found an interesting item for bid on GSA auction site if anyone
> interested.
> >
> > Reminds me of General Data equipment...
> > https://gsaauctions.gov/gsaauctions/aucitsrh/?sl=31QSCI22048010
> >
> >
> > Sorry, link did not send correctly on first try.
> > Stan Irwin
>

Re: DEC H500 Digital Computer Lab

[Tom Hunter via cctalk]

Hi Ethan,

My count is zero. I had no original patch wires at all.   :-(
I made mine from some cheap banana plugs and silicon leads I bought on
AliExpress.
Only about 30 % of the plugs were a good fit, the rest I had to modify to
make them usable.
The YouTube video from my original post shows the patch wires I made.
The originals were using 0.1" taper pins, but I never saw an original
(other than photos).
I couldn't find a source for the correct 0.1" taper pins so the banana
plugs were my next best choice.

Tom

On Sat, Mar 12, 2022 at 1:35 AM Ethan Dicks  wrote:

> On Fri, Mar 11, 2022 at 8:03 AM Tom Hunter via cctalk
>  wrote:
> > As there is no real cctalk traffic other than test messages I thought I
> > post something a bit more interesting. Here is a short video of my fully
> > restored DEC H500 Computer Lab with an 8-bit counter implementation
> > including reset:
>
> Hi, Tom,
>
> Great post and timely.  I recently got leads for my H-500 but I didn't
> get exactly "one set". I know I didn't get any of the longest wires
> but I also got a couple extra, I think, brown ones for the tips.  I
> read through the handbooks and the closest thing I found was page 173
> in the Workbook that mentions "Bundle of Taper-Pin Patchcords (107 of
> Assorted Lengths), Model Number 916, $30).
>
> Could you post how many of each color you have?  It's possible, of
> course, that you don't have exactly "one set" either, but if you
> happen to have 107 wires, that's a good indication, especially if your
> tally matches mine anywhere.
>
> Here's what I have:
>
> 22 BRN  ~ 3" ( 2-7/8")
> 30 RED  ~ 5" ( 4-7/8")
> 25 ORN  ~ 7" ( 6-7/8")
> 20 YEL  ~ 9" ( 8-7/8")
> 10 GRN  ~17" (16-7/8")
> 0 BLU
> -
> 107
>
> -ethan
>

DEC H500 Digital Computer Lab

[Tom Hunter via cctalk]

As there is no real cctalk traffic other than test messages I thought I
post something a bit more interesting. Here is a short video of my fully
restored DEC H500 Computer Lab with an 8-bit counter implementation
including reset:

https://www.youtube.com/watch?v=57xU3Xqnqx4

Enjoy
Tom Hunter

P.S. Is there some problem with the mailing list? The few "non-test"
messages I get are often out of context.

Re: 11/83 operating system load update -2

[Tom Hunter via cctalk]

Hi Rod,

The "*.dsk" format is just a file extension. What utility created the RX50
disk images?

Tom


On Wed, Feb 23, 2022 at 10:29 AM Rod Smallwood via cctalk <
cctalk@classiccmp.org> wrote:

> Hi
>
> Well I have had a huge response to my request.
>
> I am unsure as to if I have defined the problem properly.
>
> So a few bullet points.
>
> 1. The objective is to copy RX50 disk images (*.dsk format) to genuine
> DEC RX50 disks.
>
> 2. The PC I want to use is a DEC Celeibris FX ie the PC and its W95
> software is as supplied by DEC.
>
> 3. It has an RX33 5.25 inch floppy drive.
>
> 4. The RX33 _*is*_ capable of  reading and writing RX50 disks.
>
> 5.  putR was supposed to be able to do this. It does not.
>
> 6.  All that is lacking is the right utility.
>
> 7. Doing this does not need any disks other than RX50's.
>
> 8. Linux in any of its myriad of forms is not the answer.
>
> 9. simH is good at what it does but of no use here
>
> 10.  Its just a W95 utility program to copy an RX50 disk image to an
> RX50 disk on an RX33 drive on a DEC PC.
>
> 11. So whats it called? Does it work  given the above situation?
>
> Rod
>
>
>

Re: rotron caravel fan used in DEC and other cabinets

[Tom Hunter via cctalk]

Hi Paul,

At first I have replaced the bearings in the original two 10" fans in the
top of my LAB-8/e rack hoping to reduce the noise substantially.
The new bearings did not noticeably improve the noise levels.

After a few days of suffering through the noise I decided to replace them
with modern and quieter versions which move the same volume of air.
As I am in Australia I changed from the original 115V fans to 240V fans
which meant I no longer had to use the large 240V to 115V step-down
transformer in the back of the H960 rack.

Regards
Tom

On Mon, Feb 21, 2022 at 12:11 PM Paul Anderson via cctalk <
cctalk@classiccmp.org> wrote:

> I'm sorry, I meant info on rebuilding, bearing replacement and sources for
> bearings.
>
> That's what I get for sleep typing at 4:30.
>
> Thanks, Paul
>
> On Sun, Feb 20, 2022 at 4:33 AM Paul Anderson  wrote:
>
> > Does anyone have a video or printed procedure they can send me or point
> me
> > somewhere that could help?
> >
> > Thanks, Paul
> >
>

Re: DECTape head problem

[Tom Hunter via cctalk]

You could try: http://www.jrfmagnetics.com/

Tom

On Wed, Feb 9, 2022 at 3:06 PM Gary Oliver via cctalk 
wrote:

> On 2/8/22 14:14, Wayne S via cctech wrote:
> > Searched a lille bit for Western Magnetics.  Here’s a site that has some
> surplus heads, even a western magnetics onebut probably not the correct
> one. There is a corporate charter record for Western Magnetics in Minnesota
> dated 1964. Maybe this is the same company. There’s also a tape head from
> Michigan Magnetics. Maybe a merged company?
> >
> > https://www.surplussales.com/Equipment/magnetic-tape.html
> >
> >
> > Sent from my iPhone
> >
> > On Feb 8, 2022, at 13:05, Ron Pool via cctech 
> wrote:
> >
> > 
> > So it sermsdectape heads are special. I don’t think Dec would have the
> desire to make them internally so they probably contractef with a company
> already set up to do that. Who were the big tape head manufacturers at that
> time? Does anyone know?
> >
> > A photo of the back of a TU56 DECtape head can be seen at
> https://www.pdp8online.com/tu56/pics/head_label.shtml?small .
> > The head has a label on it that reads:
> >   Western Magnetics
> >   Glendale Calif.
> >   Record
> >   7282
> >
> > I've never seen a TU56 in person and have no idea if they have separate
> read, write, and erase heads or some other combo.  The "Record" notation on
> the above head's label hints to me this might be a write head.
> >
> > I found that and other DECtape photos at
> https://www.pdp8online.com/tu56/tu56.shtml .
> >
> > -- Ron
> >
> >
> Thanks.  Hadn't seen the Minnesota information.  Found some references
> but not actual company info.  Did find a reference somewhere it Canada,
> but I couldn't tell if it was original or successor company.  At any
> rate, no web presence nor telephone numbers found (yet.)
>
> I've dealt with the SurplusSales (of Nebraska) many times.  His prices
> are usually pretty high (not obscene, but just not 'surplus' prices I'm
> used to.)  However, he is a first-rate dealer and when he says something
> is so, you can count on it.  Never had problem with anything I was
> willing to *PAY* for.  I scanned the list you provided and found only a
> few 'digital' devices, unfortunately.  I suspect from 7 and 9 track mag
> tape drives.  I will scan his site and send him a ping so he'll be on
> the lookout.
>
> -Gary
>
>
>

IBM 129 keypunch on Ebay

[Tom Hunter via cctalk]

There is a nice looking IBM 129 keypunch on Ebay for what I think is a very
reasonable "buy it now" price of US$1799:

https://www.ebay.com/itm/333898748391

Shipping to Australia would be horrendous otherwise I would have bought it.

Best regards
Tom Hunter

Re: The Portable C Compiler (pcc)

[Tom Hunter via cctalk]

Anders Magnusson clarified that the DG Nova architecture support has been
added by him.
It was not part of the original.
It is also a work in progress so not quite usable as of now.
I will try to make it work for simple single file C programs.

Tom

On Mon, Jan 10, 2022 at 5:59 PM Tom Hunter  wrote:

> I have managed to build the latest version of Anders Magnusson's PCC.
> It won't build out of the box and requires code and Makefile changes.
> It emits valid looking Nova assembly.
> Unfortunately it needs a machine support library which is not included to
> do function prolog, epilog, shift operators, multiplications, conversions,
> some of the assignments and indirections.
> There is an old README which provides sample implementations which don't
> match the code generated by the compiler.
> With some reasonable effort I think the bare-bones Nova support could be
> made to work properly (without any target OS support).
> It would be nice to be able to do some low-level work in C rather than
> doing everything in assembly.
>
> Tom
>
> On Mon, Jan 10, 2022 at 4:34 PM Tom Hunter  wrote:
>
>> I have tried to get in touch with Anders Magnusson, but got no reply yet.
>>
>> Tom
>>
>> On Sun, Jan 9, 2022 at 11:36 PM Will Cooke via cctalk <
>> cctalk@classiccmp.org> wrote:
>>
>>>
>>>
>>> > On 01/09/2022 9:10 AM Tom Hunter via cctalk 
>>> wrote:
>>> >
>>> >
>>> > The original "Portable C Compiler" by S. C. Johnson (also known as
>>> "pcc")
>>> > had functional support for the Data General Nova. Could somebody please
>>> > point me to this original implementation?
>>> >
>>> > There is a modern C99 version of this compiler maintained by Anders
>>> > Magnusson at: http://pcc.ludd.ltu.se/
>>> >
>>> > Unfortunately in this version the Nova architecture is no longer
>>> supported
>>> > and won't build correctly although associated files are still in the
>>> source
>>> > hierarchy.
>>> >
>>> > I am looking for the original implementation - not any recent work.
>>> >
>>> > Thanks
>>> > Tom
>>>
>>> Have you contacted the author and asked him?  I suspect he has the
>>> original that he worked from.
>>>
>>> Will
>>>
>>

Re: The Portable C Compiler (pcc)

[Tom Hunter via cctalk]

I have managed to build the latest version of Anders Magnusson's PCC.
It won't build out of the box and requires code and Makefile changes.
It emits valid looking Nova assembly.
Unfortunately it needs a machine support library which is not included to
do function prolog, epilog, shift operators, multiplications, conversions,
some of the assignments and indirections.
There is an old README which provides sample implementations which don't
match the code generated by the compiler.
With some reasonable effort I think the bare-bones Nova support could be
made to work properly (without any target OS support).
It would be nice to be able to do some low-level work in C rather than
doing everything in assembly.

Tom

On Mon, Jan 10, 2022 at 4:34 PM Tom Hunter  wrote:

> I have tried to get in touch with Anders Magnusson, but got no reply yet.
>
> Tom
>
> On Sun, Jan 9, 2022 at 11:36 PM Will Cooke via cctalk <
> cctalk@classiccmp.org> wrote:
>
>>
>>
>> > On 01/09/2022 9:10 AM Tom Hunter via cctalk 
>> wrote:
>> >
>> >
>> > The original "Portable C Compiler" by S. C. Johnson (also known as
>> "pcc")
>> > had functional support for the Data General Nova. Could somebody please
>> > point me to this original implementation?
>> >
>> > There is a modern C99 version of this compiler maintained by Anders
>> > Magnusson at: http://pcc.ludd.ltu.se/
>> >
>> > Unfortunately in this version the Nova architecture is no longer
>> supported
>> > and won't build correctly although associated files are still in the
>> source
>> > hierarchy.
>> >
>> > I am looking for the original implementation - not any recent work.
>> >
>> > Thanks
>> > Tom
>>
>> Have you contacted the author and asked him?  I suspect he has the
>> original that he worked from.
>>
>> Will
>>
>

Re: The Portable C Compiler (pcc)

[Tom Hunter via cctalk]

I have tried to get in touch with Anders Magnusson, but got no reply yet.

Tom

On Sun, Jan 9, 2022 at 11:36 PM Will Cooke via cctalk 
wrote:

>
>
> > On 01/09/2022 9:10 AM Tom Hunter via cctalk 
> wrote:
> >
> >
> > The original "Portable C Compiler" by S. C. Johnson (also known as "pcc")
> > had functional support for the Data General Nova. Could somebody please
> > point me to this original implementation?
> >
> > There is a modern C99 version of this compiler maintained by Anders
> > Magnusson at: http://pcc.ludd.ltu.se/
> >
> > Unfortunately in this version the Nova architecture is no longer
> supported
> > and won't build correctly although associated files are still in the
> source
> > hierarchy.
> >
> > I am looking for the original implementation - not any recent work.
> >
> > Thanks
> > Tom
>
> Have you contacted the author and asked him?  I suspect he has the
> original that he worked from.
>
> Will
>

The Portable C Compiler (pcc)

[Tom Hunter via cctalk]

The original "Portable C Compiler" by S. C. Johnson (also known as "pcc")
had functional support for the Data General Nova. Could somebody please
point me to this original implementation?

There is a modern C99 version of this compiler maintained by Anders
Magnusson at: http://pcc.ludd.ltu.se/

Unfortunately in this version the Nova architecture is no longer supported
and won't build correctly although associated files are still in the source
hierarchy.

I am looking for the original implementation - not any recent work.

Thanks
Tom

Programming Bipolar PROMs

[Tom Hunter via cctalk]

While restoring and repairing a Data General Nova 2/10 I found a bad
bipolar PROM on the CPU board. The PROM has open-collector outputs and is
organized as 32 words by 8 bits. It appears that one of the open-collector
driver transistors is faulty (but it could also be that a fuse has
"healed").

The part is an Intersil IM5600CP, but these were also made by others, for
example Signetics and Philips made the 82S23 and TI and NTE made the faster
SN74S188N. Some vendors still sell these parts and there are even a few on
Ebay.

How do I program these PROMs? I found one somewhat obscure description of
the algorithm in the NTE datasheet, but I suspect that each manufacturer
had (somewhat) different algorithms.

Is there an affordable commercial programmer out there which can program
these PROMs?

Is there a simple design out there which I could breadboard for a one-off
programming job (maybe using an Arduino to control the programming
sequence)?

Thanks and best regards
Tom Hunter

Data General NOVA 2/10

[Tom Hunter via cctalk]

I just started working on a Data General NOVA 2/10 which is in quite
reasonable cosmetic condition, but has a number of problems.

The system comes with 8 kwords plus 16 kwords of core boards and a
"Cassette I/O" board and the CPU board.

After reforming the "man sized" caps and verified the power rails I took a
leap of faith and plugged in the CPU and the 16 kword core board. I managed
to deposit a few bit patterns and read back mostly what I deposited. After
a few power cycles I could no longer deposit values and read back what I
deposited. I also noticed that a 30 Ohm resistor rated at 3W which
previously got quite warm now stayed cold. That PCB area around that
resistor has cooked in the past and has changed colour - not dramatic, but
it obviously got quite hot in the past.

Unfortunately I didn't find a good schematic specifically for the Nova
2/10. There is one for the Nova 2/4 up on Bitsavers, but it is hard to read
and does not cover the NOVA 2/10 which is not quite the same as the NOVA
2/4. For example the power supply is completely different.

Until now I have been spoiled with quite decent DEC PDP-8/e documentation
and would be surprised if Data General did not provide a similar level and
quality of documentation. Maybe I am looking in the wrong place.

Thanks
Tom Hunter

Re: What's left of the Houston Museum stuff

[Tom Hunter via cctalk]

"Houston Computer Museum" ... I wouldn't call this a "museum". The
condition of the stuff is fitting for a garbage tip. It is a disgrace.

On Thu, Jul 22, 2021 at 6:50 AM Al Kossow via cctalk 
wrote:

>
> https://www.facebook.com/groups/2103793056560583/permalink/3118441161762429/
>
>

Re: core matt repair

[Tom Hunter via cctalk]

Hi Jos,

Resoldered how?

The wires are _very_ thin (I guess 0.1 mm or thinner - think of human hair)
and they are covered with some form of high-temperature lacquer which you
would have to remove first. Also the dimensions of all this stuff is
_tiny_. There is just no space to poke anything in to solder a joint.
Your average fine tipped soldering iron would be ridiculously large to even
try.
I wonder if spot welding would work using the tip of a fine needle.
Of course before you can even attempt to repair a broken wire you have to
locate the break.

Best regards
Tom Hunter


On Wed, Jul 21, 2021 at 1:36 PM jos via cctalk 
wrote:

> On 21.07.21 02:15, Brent Hilpert via cctalk wrote:
> >
> > In general comment to the topic, I have seen planar arrays ("mats") with
> some number of randomly-situated wire splices in them.
> > These splices are in the gaps between bit arrays, not interior to a bit
> array (there isn't enough space between cores).
> > The splices are covered in a tiny dollop of (by appearance) silicon
> putty for insulation.
> >
> I have seen the same, and measured that these splices can turn highohmic.
> I recovered an 8/L coremat by resoldering these splices.
>
>

Re: DEC PDP-8/e H212 core mat repair

[Tom Hunter via cctalk]

Thanks Josh,

I read through both patents but struggled to fully understand what they
described.
Unfortunately patents are written in broad terms to cover as much as
possible.

It was very interesting nevertheless.

Best regards
Tom Hunter

On Mon, Jul 19, 2021 at 4:52 PM Joshua Rice via cctalk <
cctalk@classiccmp.org> wrote:

>
>
>
> -- Original Message --
> From: "Tom Hunter via cctalk" 
> To: "General Discussion: On-Topic and Off-Topic Posts"
> 
> Sent: Monday, 19 Jul, 2021 At 06:33
> Subject: DEC PDP-8/e H212 core mat repair
> I am curious if anyone has attempted to repair (replace) a broken wire
> in a
> PDP-8/e H212 (MM8EJ) core mat (8 k word). The cores are not visible
> without
> a microscope. I cannot imagine how these were even manufactured and
> wonder
> if DEC service centers repaired core mat faults or if faulty boards were
> simply discarded.
> CDC 6600 cores were huge in comparison and I would not hesitate to
> replace
> a broken core wire on those.
> Best regards
> Tom Hunter
>
>
> These patents might be enlightening. I'm sure there's others, but these
> are some i've found on a quick search.
> https://patents.google.com/patent/US4161037A
> <https://patents.google.com/patent/US4161037A>
> https://patents.google.com/patent/US3668664
> <https://patents.google.com/patent/US3668664>
> Josh
>

DEC PDP-8/e H212 core mat repair

[Tom Hunter via cctalk]

I am curious if anyone has attempted to repair (replace) a broken wire in a
PDP-8/e H212 (MM8EJ) core mat (8 k word). The cores are not visible without
a microscope. I cannot imagine how these were even manufactured and wonder
if DEC service centers repaired core mat faults or if faulty boards were
simply discarded.

CDC 6600 cores were huge in comparison and I would not hesitate to replace
a broken core wire on those.

Best regards
Tom Hunter