February 2025 - cctalk - classiccmp.org

by John Robertson

I'm just starting to clean up a NeXT system that a friend has had in storage for decades... I assume the thing has a battery somewhere - I just hope it isn't Ni-Cad! This is the original cube, monitor, keyboard (& mouse?), printer, assorted cables, and a SCSI secondary hard drive box. So far the manuals haven't shown up, but that is all online AFAICT. My plan is to give them all a good cleaning, then open up and inspect capacitors, look for batteries and any other perishable items, and then do diode checks prior to considering powering up. The remembered background story was a nearby lightning strike may have taken out the (1200 baud?) external modem, so will be paying extra attention to the serial ports! Sniff test may still be useful even after 20ish years. Any suggestions on what else to watch for on this setup prior to first power? I also will be using the Dim-Bulb setup once it seems safe to turn on. Anyone seen a common problem in power supplies for these components for example? Planned destination is auction... Thanks! John :-#)#

2 months

11
14
0 0

VCF Montréal Survey

by Jeffrey Brace

This survey is in its final days. You are invited to add your anonymous input by clicking here https://bit.ly/vcfm2026pre-en Ce sondage entre dans ses derniers jours. Vous êtes invité à ajouter vos commentaires anonymes en cliquant ici https://bit.ly/vcfm2026pre-fr DATE: January 25 & 26, 2026. LOCATION: Montréal, QC, Canada Jeff Brace VCF National Board Member Chairman & Vice President

2 months

2
2
0 0

FYI: The ongoing, 40 years long search for Aleph Null

by Tomasz Rola

Howdy, The subject of Aleph Null's real identity appeared on HN... :: Who was Aleph Null? Posted on 2 September 2013 by Brian Hayes http://bit-player.org/2013/who-was-aleph-null :: https://news.ycombinator.com/item?id=43195308 Intriguing. He must have been known by somebody, back in the day. -- Regards, Tomasz Rola -- ** A C programmer asked whether computer had Buddha's nature. ** ** As the answer, master did "rm -rif" on the programmer's home ** ** directory. And then the C programmer became enlightened... ** ** ** ** Tomasz Rola mailto:tomasz_rola@bigfoot.com **

2 months

2
1
0 0

Anybody need a dot matrix impact printer?

by Van Snyder

Anybody need a dot matrix impact printer? Do you need to print multi- part forms with carbon paper or NCR paper? I have a Star Micronics SB-10 dot matrix impact printer. It has a parallel port interface. I have the cable, manual, and a spare ribbon. None of my computers have a parallel port so I haven't tried to use it. I put it on EBay, but mostly I don't want to throw it in the E-waste bin. It's yours for pickup or shipping, but I won't complain if you offer me something for it. 30lb. 20x20x10 inch box.

2 months

2
1
0 0

Thousands of new Data General documents added to the on-line archives...

by Bruce Ray

Thousands of new documents have been added to the DG legacy preservation web site [www.NovasAreForever.org], including new sections for the Nova, SuperNova, Nova 2, Nova 3, microNova, MPT, Eclipse S/130, Eclipse S/140, Eclipse S/230, Eclipse C/330, Eclipse S/280, and Desktop Generation computers.(!) Separate areas also now exist for DG disks, tapes and other peripherals. New archives for 3rd-party, DG-compatible hardware vendors have been started with this release, including those for Keronix, DCC, Bytronix and ROLM. This update reflects Wild Hare's continuing dedication [obsession?] to preserve Data General's significant part of computer history, and to help museums, universities and "restorationists" preserve DG systems worldwide. Bruce Ray www.NovasAreForever.org -- Bruce Ray, President Wild Hare Computer Systems, Inc. Denver, Colorado USA bkr(a)WildHareComputers.com ...preserving the Data General legacy: www.NovasAreForever.org

2 months

2
1
0 0

Might be antique computer parts

by Van Snyder

I have two SPST time delay 12-volt relays packaged like vacuum tubes with octal bases, Amperite models 12N010 (ten seconds) and 12C5 (five seconds). They're in their original boxes. I have no idea what devices used them. It seems a shame to throw them in a recycle bin. Does anybody want them? Van Snyder

2 months, 1 week

2
2
0 0

Rainbow 100A Video Fault (also posted on VCF)

by Rob Jarratt

I have been trying to diagnose a video fault on my Rainbow 100A for some time now. The monitor shows an error message and some of the attributes displayed are wrong and displayed incorrectly on every line down the screen. However, the attributes being presented to the DC012 appear to be correct and the DC012 is good (I have replaced it with a spare and with a known good one, all have the same behaviour), and yet the display is wrong. I have posted this on VCF, but would like to reach a wider audience as I am really at a loss now as to what the problem could be. Picture of the problem here: https://forum.vcfed.org/index.php?threads/video-ram-fault-on-a-rainbow-100a. 1250713/post-1418966 Description of what I have found here: https://forum.vcfed.org/index.php?threads/video-ram-fault-on-a-rainbow-100a. 1250713/post-1433618 Thanks Rob

2 months, 1 week

1
0
0 0

Elliott Algol

by Frank Leonhardt

As those of us with a few years will know, Tony Hoare (and Jill's) implementation of Algol 60 on the Elliott 803 was a highly significant event in the history of computer languages. It was the first practical commercial Algol compiler, launched block structures languages, and played a part in Elliott selling nearly 300 803B computers at a time when 300 computers was a big number. Obviously the US preferred Fortran and COBOL for commercial use, and there were other Algol compilers in some shape or other knocking about in universities. But I'd say this implementation put block structured programming into the mainstream. (And it was the first high level language I used, but that's beside the point). Now some kid on Wikipedia thinks it's not notable and is trying to delete it because he can't find much on it doing a Google search. Wikipedia may be sinking under activists and egos, but I think we need to put this misapprehension straight. Unfortunately we may be arguing with an idiot. https://en.wikipedia.org/wiki/Elliott_ALGOL If course, if anyone thinks it wasn't significant, that's an opinion too, but I'd like to hear why. Thanks, Frank.

2 months, 1 week

32
130
0 0

Re: Classic computers with more than one stack pointer, but not FORTH machines.

by John

On Fri, 21 Feb 2025 12:00:07 -0600 Paul Koning <paulkoning(a)comcast.net> wrote: > > What is the problem with ISRs running in a user stack? The ISR > > runs, exits, the stack is cut back, and net effect on the user's > > stack is zero. > > A stack access fault in user mode kills the process, in kernel mode > (certainly in an ISR) it kills the whole system. You can't leave the > integrity of the OS at the mercy of the application having a valid > stack. Additionally, the ISR could leave potentially sensitive information in user memory, depending on exactly how the stack and memory protection are implemented. Consider an architecture where the stack pointer is a normal address register (as on the -11, the 68k, etc.) and protection is on a per-page basis with no bounds checking (i.e. there's no special address space for the stack, just a particular chunk mapped into normal user memory.) It'd be trivial for a user program to sit and "scrape" the stack for stray bits left by passing ISRs - say, waiting to see if the UART service routine happens to jot down something that looks like an admin password coming off one of the terminals.

2 months, 1 week

4
5
0 0

Re: Elliott Algol

by Paul McJones

> On19 Feb 2025 18:39:08 -0500, Chuck Guzis via cctalk wrote: > >>> >>>> One of most ingenious coding tricks to me was the problem of saving and >>>> restoring all registers without resorting to an exchange jump. We used >>>> that one as a test for applicants. >>> >>> Argh... I know I've seen this trick, but it's been too many years. How >>> about a hint? >> >> It uses the RJ instruction to record register content, bit-by-bit. >> Think about it--RJ is about the only instruction that can modify memory >> without fiddling with the A6 and A7 registers. >> > > Of course... I vaguely recalled there was a bit-by-bit save, but didn't > think of the RJ. Thanks. A full example of this code is in the DEBUG package of CAL SNOBOL <https://mcjones.org/CAL_SNOBOL/>, starting at label SAVEREG: Original version: https://mcjones.org/CAL_SNOBOL/UArizona/SNOBOL.MAC.html Revised version: https://mcjones.org/CAL_SNOBOL/UTexas/DEBUG.html

2 months, 1 week

1
0
0 0

IBM 4506 (old message)

by Tommy Chang

I saw an email posted to the predecessor mail list asking if anyone had a picture of an IBM 4506 terminal. I was looking through the September 1973 issue Modern Data and saw an article on page 70 about the New York Times’s indexing efforts. It said that they were using IBM 4506 terminals and it has a picture of a large workroom (identified as “The Times index room”) with a bunch of terminals which I assume must be 4506’s (although the caption does not explicitly state that). The magazine is available on BitSavers. Look for the issue with file name Modern_Data_1973_07.pdf. Tommy Chang

2 months, 1 week

1
0
0 0

Classic computers with more than one stack pointer, but not FORTH machines.

by ben

Did any classic computers have a subroutine call as (S++)=PC, PC=(EFA) as well as the standard call (--S)=PC,PC=(EFA) ? One could have a virtual stack machine, using helper functions without having to deal with return addresses on the stack. Ben.

2 months, 1 week

16
27
0 0

Re: Classic computers with more than one stack pointer, but not FORTH machines.

by John

On Tue, 18 Feb 2025 12:00:10 -0600 cctalk-request(a)classiccmp.org wrote: > On the more than "one stack pointer" in the subject, it was a bit > arbitrary on the PDP-11 (or VAX) as the pre/post indexed indirect > addressing made every register a stack pointer. But this is where I > get hazy between DEC and 68K, and I did a lot more 68K. I'm pretty > sure you could do a move.l PC, An and you could certainly do an > indirect jmp (An), so effectively you could have multiple call stacks > if you wanted. Almost, kinda-sorta. The JSR and RTS instructions are hard-wired to use R6/SP, and there's nothing you can do about that. You *can* implement a return off another "stack" by doing e.g. MOV @(Rn)+, PC as long as you save the return address by hand, first - but this affects the flags, unlike JSR/RTS.

2 months, 2 weeks

1
0
0 0

HAWLEY X063X Mark II and XEROX Star mice

by hupfadekroua

Hi all, I‘m offering HAWLEY X063X, XEROX Star rollerball and optical mice. If interested contact me offlist please. Best Andreas

2 months, 2 weeks

1
0
0 0

VCF SoCal 2025 recap

by Steve Lewis

Happened to be in the area, so I checked out VCF SoCal last weekend. Glad I did, wow Lee Felsenstein was able to present ! What a treat. VCF SoCal 2025 — voidstar <https://voidstar.blog/vcf-socal-2025/> https://voidstar.blog/vcf-socal-2025/

2 months, 2 weeks

1
0
0 0

Re: Elliott Algol

by Paul McJones

> On 15 Feb 2025 18:41:21 -0800,Van Snyder <van.snyder(a)sbcglobal.net <mailto:van.snyder@sbcglobal.net>> wrote: > > Harry Husky, the G15 designer, was one of the computer design pioneers. > He became a professor (maybe adjunct) at UC Berkeley. As far as I know, Huskey was a regular professor. Two of his Ph.D. students went on to win the ACM Turing Award: Niklaus Wirth and Butler Lampson: https://mathgenealogy.org/id.php?id=10185 Huskey went on to found the Computer Science department at U.C. Santa Cruz.

2 months, 2 weeks

2
2
0 0

Re: Elliott Algol

by Paul McJones

> On 16 Feb 2025 18:00:35 -0700,ben <bfranchuk(a)jetnet.ab.ca <mailto:bfranchuk@jetnet.ab.ca>> wrote: > > I have trouble understanding the fine points of accessing a local > variable in Algol with a display. Books tend to spend more time > on the evils of a dangling else, and gloss over the run time action of > a display. > Have a good example or reference book I can find free on line. The original book on that subject is ALGOL 60 Implementation by B. Randell and L. J. Russell. It’s available here with permission from the copyright holder: https://www.softwarepreservation.org/projects/ALGOL/algol60impl/#ALGOL_60_I…

2 months, 2 weeks

1
0
0 0

Open source a panacea?

by Donald Whittemore

I am an old mainframe guy. I could give you my COBOL deck of cards or the compile listing. You could pour through the code looking for nefarious/malicious code. I then hand you the object deck. You have no idea if it matches the code you looked at. The only way you could be sure is to compile the code I gave you and use your own object deck. So why is open source these days such a beneficial thing? DeepSeek may be open source but I have no way to create my own executable. Besides, I don’t know what language it is written in but I bet I have no expertise in it. No way to for me to identify nasty code. Yes, many people may have reviewed the code but that does not mean what I am running is the result of that code.

2 months, 2 weeks

21
50
0 0

Re: Elliott Algol

by Dr. Erik Baigar

Hi Van, just wanted to point out, that there is a 803 emulator out there: https://www.peteronion.org.uk/Elliott/ I have got a real 900 series machine running, which is from the very early 1970ies and also runs a form of Elliott Algol: https://www.youtube.com/watch?v=v-gF5g0nnoE Best wishes, Erik. ---------------------------------------------------------------------- ''~`` ( o o ) +--------------------------.oooO--(_)--Oooo.-------------------------+ | Dr. Erik Baigar Inertial Navigation & | | Salzstrasse 1 .oooO Vintage Computer | | D87616 Marktoberdorf ( ) Oooo. Hobbyist / Physicist | | erik(a)baigar.de +------\ (----( )---------------------------+ | www.baigar.de | \_) ) / +----------------------+ (_/

2 months, 2 weeks

1
0
0 0

Re: RS232 then and now

by Robert Feldman

>Message: 31 >Date: Sun, 2 Feb 2025 07:29:15 +0000 >From: Tony Duell <ard.p850ug1(a)gmail.com> >Subject: [cctalk] Re: RS232 then and now > >On Sat, Feb 1, 2025 at 10:54 PM Fred Cisin via cctalk ><cctalk(a)classiccmp.org> wrote: > > >> >> IBM used a DB25 socket for their printer port at the computer end, >> (male on the card for serial, female on the card for parallel "Centronics") >> THAT, of course caused some idiots to attempt to use the parallel port for >> serial and vice versa. "I just need a 'gender changer'!" :-) > >The worst screw-up there (IMHO) came from HP in the HP150 series. This >machine had 2 RS232 serial ports as standard on DB25 sockets, wired >for some inexplicable reason as DTEs. There was an add-on board that >included a parallel printer port. To avoid confusion, this was a DB25 >plug. But the board had been laid out for a DB25 socket using the IBM >PC pinout. The result was that stb/ ended up on pin 13, D0 on pin 12, >and so on. > >-tony > My vote for the worst connector screw-up is the AT&T (Olivetti) 6300. Its monochrome monitor used a DB25 to supply both the signals and 12 volts to power the monitor. Bob

2 months, 2 weeks

7
8
0 0

RS232 - parallel modems!?

by Steve Lewis

I was about to ask if anyone ever built a "Parallel Modem" - but I searched around first, and lo and behold, Microcom did ! (v.fast / v.34 era, c. 1996) The drivers refer to Win3.1/Win95 era (I'm not seeing where they had DOS support). But I'm still not sure if I'm understanding the product (which I found described here Microcom Parallel Port Modem <https://strom.com/pubwork/cw294.html> From a programming perspective, you just set your parallel bits and mash the STROBE pin, right? Then figure some reasonable delay between iterations of doing that. You don't need starts/stop or parity bits. So I get how that is more efficient (but question is, why wasn't it built sooner? I think it's a long answer when you look at the historical build up of modems, and that serial-port based modems were "fast enough" at the time) So.. If you had a slow system that couldn't really take advantage of a ~7MHz 16550 serial card (or I guess like a laptop that was stuck with an older UART) That might be the use-case where this parallel v.fast might help (by being able to "feed the modem" fast enough to actually take advantage of the faster modem speed?) Or is there some other scenario NOTE, in the articled linked above, it does mention that it is only "value added" if you have this parallel-modem on both sides of the connection. (this is because you'll be flow controlled to whatever is the slower device in the connection?) Related but different question: Is there any "natural rate" (Hz) of a modem? Meaning is 1200/2400 baud-equivalent modem an accelerated-by-enhanced-encoding version of 300 bps? and 9600 likewise an accelerated-by-encoding version of 2400? is 300bps itself some kind of special accelerated-by-encoding? I see 1200 baud was also still sub 3KHz (did any modem protocol go above 3KHz?). Or maybe I need to ask it this way: did 300 baud modems use a more 1:1 translation of the data-word bits into Hz signal over the modem (giving a more "natural" translation rate?) But then beyond that speed, does a modem need to "cache" a few bytes and determine some encoding scheme to then give modems an apparent speed boost? (is that "kind-of" like USB's 8B/10B? (not in implementation, but in the general concept that a different encoding can result in improved data throughput, without actual faster movement of that data?) I guess it gets into the "secret sauce" approaches of how vendors figured out these encoding approaches (v.32bis, etc), and give their product competitive advantages (but only if you could convince enough ISPs to adopt your protocol, by buying your modem device). My daughter made me finally watch Blackberry recently, it's an interesting telling of that story (of a small business selling their tech to USR, and also that they tackled a version of encryption) -Steve

2 months, 2 weeks

20
44
0 0

"Re: Re: Elliott Algol"

by Paul Pierce

Al has a reader at CHM. They can read tapes too, my 7-track setup is now at System Source. Paul > On Sat, 2025-02-15 at 14:52 +0000, Sid Jones via cctalk wrote: > > IIRC, I have a copy of the Elliot 803 A-103 Algol compiler on a five- > > hole > > tape in a drawer somewhere in my untidy office... > > > > As used in UCNW Bangor, 1971-1974. > > There might be a reader somewhere. If anybody has (or developes) an > 803B emulator, it would be nice to have the compiler. > > Paul Pierce read several IBM 1401 tapes. The Computer History Museum in > Mountain View, CA has two operating 1401s, and the SimH project has an > emulator. It's nice to have the Autocoder assembler, FORTRAN II and > FORTRAN IV compilers, COBOL compiler, â¦ to use. There are students at > San Jose State University who go to classes in 1401 programming at CHM. > > Maybe Paul has a paper tape reader too. > > > >

2 months, 2 weeks

1
0
0 0

Dan Sokol (and bits about the Apple I and the 6502 procurement)

by Jim Brain

https://thisistrue.com/sokol-behind-scenes/ It's probably not overly important how the 6502s got sourced for the Apple I, but here's a different take. Debate as you see fit, I'm just the messenger. Jim -- Jim Brain brain(a)jbrain.com www.jbrain.com

2 months, 2 weeks

1
0
0 0

RS232 then and now

by Steve Lewis

Hey all! So, I've found myself studying up on RS-232 this year for a few reasons. I'm mulling over doing an RS232 themed talk at June VCF. Not a super exciting topic, but I do think that RS232 has an interesting history: In the SAGE relationship, and as a follow up to (essentially) prior telegraph communication. From what I've read, "50 baud" was a kind of an initial goal to beat, since that's what the top telegraph operators could achieve (in small burst, probably not all day). And those operators did have to also deal with things like start/stop "bits". Maybe it wasn't an intentional goal, but just that it establishes why "50 baud" is generally the lowest we ever see mentioned (or, if you go slower than that, might as well use the older tech). Then 75/110/130 baud to have digital-systems interoperate with classic mechanical teletypes. Going any faster and those systems jam up or overheat? These weren't yet called "serial ports", so I'm not sure what a late 50s system would even call their equipment that facilitate this data exchange (since I'm not sure what kind of crystal-clock they even had yet). Then, was it the SAGE program that demonstrated the idea of doing this kind of data exchange across copper phone lines? That is, the idea of computers collaborating not just in a room, but across long distances (miles)? And doing so by using an audio tone presentation? (they settled on around 3100MHz, which ended up translating to 300 baud? hence, that's basically why the first digital to digital system data exchange settled on that baud rate, which was reliable on both 50 and 60Hz power systems, and meaningfully faster than prior 110 baud - so a good milestone to turn it into a product, which was the Bell Model 103?). I couldn't find much details (like a manual) on the Bell 101 equipment (anyone seen one or have a manual?). But I did find the Bell 103 manual - the photo of its innards is grainy, so I don't understand how the Bell 103 did 300 baud without a UART (and one of the pinout lines I see did run power, so not sure if that's-yet RS232 or not; I know RS232 was evolving right at that same time circa 1962). I've about the 1970ish TR1402 initial DIP UART, with anything prior being an experiment (like a full board concept by DEC). I know from 1962, both RS232 and ASCII standards still took maybe another decade to really gain traction as standards (at least, from what I've read). Getting the world to comply with any standard always takes a lot of effort (for a practical reason of everyone still having invested in the older tooling that was still functional). But it's interesting how those two standards are still in use (not in their original form, but least the 1967 revisions) - extending from Baudot.and late 1800s-tech on telegraphs. Does anyone know of any grocery stories using RS232 in the 1960s? I think barcode scanning was just introduced in that era. I can just imagine a smart grocery store owner, in the backroom programming their minicomputer for payroll and inventory management. In FORTRAN and without a CRT? Actually, in the 60s, I think included software would be negotiated with the provider of the computer (well, I'm not sure how that differed between minis and mainframes). I know early microcomputers used RS232 for keyboards (1974-1976 era). The IBM PC keyboard is essentially another form of serial. Well, sorry for the rambling - have other RS232 related questions, but first wanted to focus on the historical aspects (and see if I'm somewhat on the right track at least). -Steve

2 months, 2 weeks

31
114
0 0

Ad-blocking (was Re: Open source a panacea?)

by John

On Fri, 14 Feb 2025 12:00:07 -0600 cctalk-request(a)classiccmp.org wrote: > I can't believe people do use it any more without filtering. I've > used an ad-blocking web browser for some years but I occasionally see > the real thing when setting up a new machine. Absurd. It really is astonishing how bad it's gotten - fully the equal of the early '00s when sites might just spawn a dozen pop-ups and only one of the major browsers let you block them, only now there's a pile of JS mining crypto in the background, to boot :/ Been running with NoScript and an ad-blocker as my standard configuration for many, many years now, but it's always sobering to get a look at what other people see...

2 months, 2 weeks

3
2
0 0

2025

2024

2023

2022

cctalk February 2025