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101090 discussions

Compilers and languages (Was: Help reading a 9 track tape

by cclist＠sydex.com

On 8/3/21 1:12 PM, Paul Koning wrote: > > >> On Aug 3, 2021, at 3:28 PM, Chuck Guzis <cclist at sydex.com> wrote: >> >> ... >> One of my favorite 6000 bits of code was the register save and restore >> routines (not using CEJ). It was a favorite interview question for >> those job seekers claiming to be proficient in COMPASS. > > ALL the registers, right? I remember seeing that problem description. And later I saw the code, don't remember it but now I know how it is done. Yup, the trick is getting the first 18 bit register saved. Not obvious since normal stores are done through the (A6,X6 and A7,X7) registers. The trick is using RJ instructions to store an indication of each bit of a B-register. After you get one register saved this way, the rest falls out like a stacked deck in Solitaire. --Chuck

5 years

Europe-based restorer of old mechanical keyboards?

by lproven＠gmail.com

I am not a collector exactly -- I just salvaged a bunch when they were being sent to recycling. My Model Ms are going strong, no bolt mod needed, but I also have 2 Apple Extended II and an Extended I and both, sadly, need some attention. I am almost devoid of electronics skills. Does anyone know of anywhere in Europe that does this kind of repair/refurb work? I do not want to do intercontinental shipping... -- Liam Proven ? Profile: https://about.me/liamproven Email: lproven at cix.co.uk ? gMail/gTalk/gHangouts: lproven at gmail.com Twitter/Facebook/LinkedIn/Flickr: lproven ? Skype: liamproven UK: +44 7939-087884 ? ?R (+ WhatsApp/Telegram/Signal): +420 702 829 053

5 years

Skew vs. interleave

by mhs.stein＠gmail.com

There's a small discussion on S100computers about the terms 'skew' and 'interleave'. In CP/M documentation 'skew' refers to what's usually called interleave these days, i.e. offsetting sectors on a track to compensate for the fact that by the time the computer has processed a given sector the next one has already passed by, so that the computer has to wait an entire revolution for it to pass by the head again; in other documentation as in Chuck's 22disk for example this is also called 'interleave'. However, in later documentation the meaning of 'skew' seems to have changed to refer to the offset of sectors between adjacent tracks to compensate for the time required to step the head. Can anyone (Fred, Chuck?) shed some light on this apparent double meaning of 'skew'? And if skew was used to describe sector interleave then what was the offsetting of sectors between tracks called? Inquiring minds need to know ;-) m

5 years

For sale: FANUC Tape Reader and Adapter

by billdegnan＠gmail.com

I put my FANUC tape reader for sale on Ebay, if anyone might be interested:

5 years

Branching the thread away from Compaq deskpro boards: "What We Have Lost"

by lproven＠gmail.com

This was a talk at a recent Chaos Computer Club congress: https://media.ccc.de/v/rc3-525180-what_have_we_lost#t=1707 ? We have ended up in a world where UNIX and Windows have taken over, and most people have never experienced anything else. Over the years, though, many other system designs have come and gone, and some of those systems have had neat ideas that were nevertheless not enough to achieve commercial success. We will take you on a tour of a variety of those systems, talking about what makes them special. In particular, we'll discuss IBM i, with emphasis on the Single Level Store, TIMI, and block terminals Interlisp, the Lisp Machine with the interface of Smalltalk OpenGenera, with a unique approach to UI design TRON, Japan's ambitious OS standard More may be added as time permits. ? It talks about Lisp Machine OSes, which interest me, but I especially liked that there's a demo of Interlisp as well as the better-known Symbolics OpenGenera. Unlike Genera, Interlisp is now FOSS and there is an effort afoot to port it to modern OSes and hardware and revive it as a Lisp IDE. There's also a not-very-inspiring but all too rare demo of IBM i. It's not pretty but this descendant of OS/400 is the last living single-level store in active maintenance and production. But the big thing that made me link to this after the discussion of DOS/V, Chinese Windows 3.2 and Japanese DR-DOS and DR GEM, was the demo of the final version of Japan's TRON OS. Most people have never heard of TRON but it was extraordinarily widely-used, embedded in billions of consumer electronics products. Well, there was also a desktop-PC version, with its own very rich object-oriented GUI, and this talk contains the only demo of it I've ever seen. -- Liam Proven ? Profile: https://about.me/liamproven Email: lproven at cix.co.uk ? gMail/gTalk/gHangouts: lproven at gmail.com Twitter/Facebook/LinkedIn/Flickr: lproven ? Skype: liamproven UK: +44 7939-087884 ? ?R (+ WhatsApp/Telegram/Signal): +420 702 829 053

5 years

Reading MT/ST tapes

by len＠shustek.com

>Date: Wed, 28 Jul 2021 18:37:17 -0500 >From: Cory Heisterkamp <coryheisterkamp at gmail.com> > This is a bit of a long shot, but is anyone aware of a successful > method to read IBM Selectric MT/ST tapes? > A museum in Australia has a box of them and are interested in the contents. At the Computer History Museum we sometimes use a software technique to recover data from the analog waveforms on mag tapes. https://github.com/LenShustek/readtape I'd like to try that on MT/ST tapes. Does anyone have a couple of MT/ST tape cartridges with data that I can experiment with?

5 years

Unidentified IBM Module / Package

by coryheisterkamp＠gmail.com

Does anyone recognize these IBM modules? My gut says late 50?s based on the transistor packages and font. Perhaps for a contract or military system? Thanks- Cory https://www.dropbox.com/s/izitf1lmjqwcbuo/IBM1.jpg?dl=0 https://www.dropbox.com/s/dq8macaubrechkz/IBM2.jpg?dl=0

5 years

Help reading a 9 track tape

by jimliu＠umich.edu

Hi, I have been lurking for a few years, but thought I'd finally speak up as I just received a 9 track tape purportedly containing the source code to Schoonschip (https://en.wikipedia.org/wiki/Schoonschip). This is a 2400' reel recorded at 1600 bpi based on the labels, and a cursory examination suggests that it is still in pretty good shape (although I am not sure how it was stored over the years). Here is a picture of the tape: https://drive.google.com/file/d/1JgY8QdVDchxubUz39jYn86gEczSvFhcZ/view?usp=… We no longer have any equipment that can read the tape, so I was wondering if anyone may be willing to help or if anyone had suggestions on where to go to get it read. Thanks! - jim -- James T. Liu, Professor of Physics 3409 Randall Laboratory, 450 Church Street, Ann Arbor, MI 48109-1040 Tel: 734 763-4314 Fax: 734 763-2213 Email: jimliu at umich.edu

5 years

Ian Hirschsohn - DISSPLA, Superset Inc. and sad news

by rdawson16＠hotmail.com

As some here know, I collect some dusty deck fortran graphics. We have MOVIE.BYU up and running! (Thanks Douglas Taylor and Emanuel Steibler). Ian built AMD 2901 bit slice hardware to run his graphics, it was called SuperSet, and was very quick for the 1980s. Architecture was 48 bit, A=B op C, similar to DSPs. Compiler processed fortran to this 48 bit 2900 hardware (he wrote the compiler too). Small package, a dormitory size refrigerator with all I/O to drive plotters and graphics terminals. I went to look him up today, as he is not far from me in LA, San Diego, and a fellow R/C flier, and chat about the old Superset days, we did SIGGRAPH many times together. Well, he is dead I find out, killed last year in Mexico is what the news says, buried in a well with his wife. They went often, many times a year. Randy

5 years

Reading MT/ST Tapes

by coryheisterkamp＠gmail.com

This is a bit of a long shot, but is anyone aware of a successful method to read IBM Selectric MT/ST tapes? A museum in Australia has a box of them and are interested in the contents. I'm fairly involved in the global Selectric community and while 1 or 2 MT/ST?s exist, they?re non-functional. I know IBM offered a 2495 Tape Reader for the IBM 360, which could be a starting point with modification, but I suspect those are even scarcer than the MT/ST itself. Even the encoding format appears to be a bit of a secret. Recording is character-by-character, tape spacing controlled by sprocket holes along one edge. https://obsoletemedia.org/ibm-mtst/ <https://obsoletemedia.org/ibm-mtst/?fbclid=IwAR28c5ej69AlF0os1PcykpHCh0Q_yz…> Thanks- Cory

5 years

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