October 2024 - cctalk - classiccmp.org

Identify 14" HDD with two heads on single arm

by pbirkel＠gmail.com

Can anyone identify the 14" HDD seen in the following photo (not mine)? It's unusual in that there are two moving heads on the top surface of the platter. I presume that there's a fixed head on the bottom surface for the clock track. This is from a Data General 6100 disc subsystem which is advertised as 25MB capacity. There's a related model with half that capacity. https://forum.vcfed.org/index.php?attachments/img_5116-jpeg.1288418 The only thing that I can say for sure is that it's visually not a Shugart SA4000 and that exhausts my knowledge on the subject.. While I presume that the 25-signal twisted-pair ribbon cable is for control signals, there is also a 16(?) line grey ribbon cable connected to the left side of the DG-specific power control PCB. I'm guessing that would be data/clock lines from hidden electronics where the 25-signal twisted-pair ribbon originates; not sure what else may be then happening on the DG-specific power control PCB. Thank you for any insights into manufacturer, model, and documentation. -paul

11 months, 3 weeks

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GE Mark I/Mark II Timeshare Systems

by Rick Bensene

Hello, all, I know that there has been great effort to gather up and make available via emulation (SIMH) timeshared Operating Systems for DEC machines, as well as Hewlett Packard 2000-Series Timeshared BASIC systems, but I was wondering if there has been any efforts made to archive and perhaps emulate any versions of General Electric's timesharing systems? GE's architecture was similar to Hewlett Packard's timeshared BASIC (2000A, C, C', F, /ACCESS) in that there was a main computer that took care of managing the user-space and running user programs, and a communications processor that acted as the front-end that did the terminal services handling. At one point, GE's timesharing system service was the largest timeshared computing service bureau out there, getting an early start in timesharing out of the timesharing research done at Dartmouth, as GE computers were used in this research. The GE timeshare service had local dial-up lines in most major cities, and eventually were connected into Tymnet, further adding to the places where a local dial-up number could get you into any of a number of different GE timeshare systems that were connected to the network. Has anyone done work on emulating any of GE's processors (200-series, 400-series, DATANET machines) that were used in the Mark I and Mark II timesharing systems? GE's place in timesharing history is quite significant, and seems certainly deserving of efforts to procure and preserve the code, and perhaps make it live on through emulation. However, GE being the huge entity that it is (and was back then), getting hands on the code as well as permission to do anything with it could be a challenge that may have been attempted and failed who knows how many times over the years. I'm just wondering if anyone out there may have old listings, mag-tapes, or card decks laying around that have the source(or binary distributions) for any of these GE timesharing systems? If, so, any such media should certainly be put in the hands of an entity that can assure that they are preserved, and perhaps at some point, made available online so that others who may have interest could begin work on emulating these systems. I thought of this today because an old memory came to the fore out of the blue. The memory is very clear despite the many years that have elapsed since then. It is as clear in my mind as it was the day it happened. I have no idea why it has stuck so clearly in my mind. Back in high school, there was a service man that would come in to repair/tune-up the Teletype model 33-ASR's we used to dial into the school district's HP Timeshared BASIC system. These machines were heavily used by students who didn't always treat them gently, and the 33-ASR's weren't really designed for the use they were exposed to, so he would come in frequently to fix machines that had broken down. After he had worked on a Teletype, he would dial-in to some kind of timeshare system with a local phone number and run some test programs to validate the proper operation of the terminal. and then log his work by running a BASIC program that would ask him questions about the job, and he'd fill in the answers. One day, I happened to be working at a Teletype next to the one he was working on, and he had just finished up his work on the machine. He and I had chatted numerous times in the past, so he was comfortable with me, as I was with him. I watched as he dialed up the phone number for the system and I memorized it as he dialed it. I also watched as he entered his account to log into the system. It was IBB00999, and the password was "INFO". I couldn't see the print out from my angle, so I had to watch his fingers as he typed in the information. I tried to be as inconspicuous as possible while watching him, but he made no attempt to block my view or otherwise keep me from seeing what he was doing. He always made a point of taking the printout of his session with him rather than leaving it on the machine or tearing it off and tossing it in the trash. I figure that was a security measure as the at least the user ID would be listed on the paper. But, it didn't stop someone from watching him enter the information. I had become pretty good at watching people's fingers on the keyboard to figure out what they were typing. After he had finished his work, I dialed up the system, and when it asked "USER NUMBER--", I typed in "IBB00999,INFO", and pressed [RETURN]. I guess I had observed what he'd typed correctly, because then the TTY clattered out "SYSTEM--", which I did not happen to note the service man's answer to this query, but I figured it wanted to know what language to use, so I typed in "BASIC", and hit [RETURN]. The system then said "NEW OR OLD--", and since I didn't know what programs were already in the directory, I typed in NEW, and then pressed [RETURN]. I was then greeted with "READY". I'd seen this NEW/OLD used on a DEC RSTS/E system, so I knew it meant either to start fresh with a new program, or if OLD was typed, it'd want to know the name of a program to load from the catalog. I typed in a simple BASIC program, something like generating a listing of numbers and their square roots from 1 to 100, and typed "RUN", and it paused for a short time, then began rattling off the list of numbers. I got nervous, though, and logged out after the program finished (I didn't know how to stop it, though I later figured out that pressing the [BREAK] key would work, just like it did on the HP Timeshared BASIC system. Over the following days, I logged into the system and played with it here and there, making sure to only log short sessions so as not to rack up too much time, as the company that the service guy worked for may have been charged for the online time. I never stayed logged in for more than perhaps 10 minutes at a time, and the programs I tried didn't chew up much in the way of resources. I didn't save any programs, nor did I try to do anything that would leave traces of my visits, other than the fact that I had dialed in and logged in. The system seemed to have a FORTRAN subsystem also, and I was able to enter a small FORTRAN program and RUN it, which was kind of cool. I had learned FORTRAN by taking a class at a local community college that had an IBM 360/30, so I knew enough to be able to enter a simple FORTRAN program and try it out. I thought it was really cool that this system could do both BASIC and FORTRAN. I tried to see if it had COBOL (which I had also learned by taking another class at a community college), but alas, it did not. I don't know if the languages on the system were interpreted, semi-compiled (into pseudo-code which was then interpreted), or fully compiled into machine code. I do know that when you typed RUN to execute a program, the system would pause for some time before execution began, so there must have been some kind of processing going on that could have been compilation of some form. I remember that the system seemed to be quite a bit more responsive than the HP 2000C Timeshared BASIC system the school had access to. It would generally respond to commands immediately, while sometimes the HP system would pause a bit before anything happened. Admittedly, I knew that our HP 2000C system was very busy all the time during the school days as it was shared by quite a few different school districts in the county. I had no idea how many users may have been on the GE timeshared system. It would take longer on the GE system after you typed RUN on a BASIC program before the program started executing, but once it did, it would rip through the program considerably faster than the HP system, especially when it came to doing lots of math. I once entered a program that would calculate factorials, and I ran the programs side by side, one on the HP 2000C, and the other on the GE timeshared system (I didn't know it was a GE system at the time, but figured it out later). I gave the GE system a little head-start because of the processing before the program ran. The program would generate a list of integers and their factorials from 1 to 40. As the numbers got larger, the HP timeshared system would print out the integer and some spaces, then stop for a bit, taking longer as the factorial was computed, and then print the factorial. The program was the same on both systems, but the GE system never paused during the output, and finished just under a minute faster than the HP system. I didn't have any manuals or other documentation for the system, and so I just had to trial-and-error my way through. I'm sure I didn't even begin to scratch the surface of the capabilities of the system, but it was nonetheless interesting to poke around in a system that was different than our timeshare system. After I had tinkered around with it intermittently for a few weeks, I ran out of things to try, and stopped playing with it, partly out of worry about getting caught somehow. A few months later, I thought about it again, and when I tried to login, it appeared that the user had been deleted or the password changed. Perhaps my tinkering had showed up as a larger than usual bill for services, and that resulted in the change. Or, maybe it was policy to change the user/password every so often. It was fun to explore while it lasted. The Teletype service guy would be much more careful when he was dialing up the system and entering his userID/password, and would ask anyone nearby to please turn away while he was connecting up to the system. I have no idea if it was my tinkering that caused this change in behavior, but if I was nearby, I would comply with his request, so I never got a chance to gather up another userID/password. Some years later, my father's business, which was a precision machine shop, had an account on a GE Timeshare System that had the "APT" "part programming language" that was used to describe a machined part. When the APT program was "compiled", it would result in a punched paper tape that would be fed into a Numerically-Controlled machining center to actually create the part. It was very expensive to use, and though my Dad did let me log in once and look around a little, I didn't want to rack up charges, and stayed away from messing with it. The service was discontinued when MASTERCAM came out for the IBM PC and they bought a couple of high-end PC clones and licenses for MASTERCAM. Anyway, enough old memories. If anyone out there had experience with GE timeshared systems, or may know of existence of any distribution media or source listings of the systems, or perhaps has memories of using them, I'd love to read about it. If you think it might be of general interest to the list, post it to the list, but you are certainly welcome to send it to me directly at moc-dot-enesneb+at+bkcir (backwards with special characters spelled out to hopefully prevent it being snarfed up by 5p@mm3rZ). Thanks for reading, and best to all! Rick Bensene https://oldcalculatormuseum.com Beavercreek, Oregon USA

11 months, 3 weeks

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Recovering intel intellec microcomputers, hardware and software

by jonesthechip＠logicmagic.co.uk

As the venerable intellec microcomputers have reached their half-century, I'm interested in contacting other owners/collectors to try and obtain original assembler tapes (or their contents) to enable restoration of systems to full working order. My particular interest is in the intellec 4 mod 40 (I've rebuilt the one I used in college, 1975-1977) but I don't have the original software, supplied on paper tape. I've also been in contact with other owners and people interested in making replicas of the intellec 8 and mod 80 systems, and there's a lack of info on the the ROM monitors. Given the historical significance of these fine machines (and my personal annoyance at the lack of foresight I had as a callow postgraduate regarding hanging on to copies of paper tape) I'd like to put a shout out to see if any of this information/software is available in a historical nook or cranny somewhere in the computing world and try to gather it together to help complete systems and share the techniques used when 4K of RAM was a really big, expensive and rather hot deal....

11 months, 4 weeks

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Looking for a A990 20-slot chassis

by Jesse Dougherty

Does anyone have a 20-slot HP 1000 990 chassis p/n A2959 / A2999 for sale? I can also trade for other 1k / mx HP related hardware. Feel free to email me direct off group to Jesse(a)Cypress-tech.com Thanks Jesse Jesse(a)Cypress-tech.com

12 months

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Re: Ward Christensen NY Times Obituary

by Fred Cisin

On Wed, 23 Oct 2024, Mike Katz wrote: > I agree with you but phrased differently. XMODEM is ubiquitous but CBBS created a > totally new way of sharing information and is the forerunner of everything from > CompuServe to the internet, instant messaging and even social media. > > Most people reading an obit would not appreciate the significance of a data transfer > protocol however the first "social media" type message system they would understand. Community Memory (Lee Felsenstein, Ephrem Lipkin, et al) preceded it by about five years. BUT, CBBS was the first with dial-up access [from home], rather than dedicated publicly available terminals. -- Grumpy Ol' Fred cisin(a)xenosoft.com

12 months

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Re: RSX11M installation on real PDP11

by Lee Gleason

On 10/19/2024 12:00 PM, cctalk-request(a)classiccmp.org wrote: > [cctalk] Re: RSX11M installation on real PDP11 >You may want to use simh (where you'll be able to mount tapes and RL02 >images) to do the installation and generate an RD32 image. Once you have >the disk image, use vtserver (note - some versions are limited to 32MB >images, but there are some that remove that limitation - check if the >struct vtcmd in vtserver.c uses 2 or 4 bytes for the block number), or >PDP11GUI (Windows only) to transfer the RD32 disk image to your PDP over a >serial port. If you go this route, be advised, that SIMH creates RD32 disk images are not the same size as a real RD32. This will likely cause problems when writing a SIMH created image to a real disk (and I'm not talking about the additional issues that the trailing metadata on disk images from the Pizzolato version of SIMH can cause - the problem I'm describing is caused by an incorrect disk size value in SIMH). -- Lee K. Gleason N5ZMR Control-G Consultants lee.gleason(a)comcast.net

12 months

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Re: Might be antique computer parts

by donald donaldwhittemore.com

I rue the day I lost an eBay auction. It was a PR photo with a good looking model mounting a disk in an open drawer of a 2314. If you looked carefully you would see she was holding a 2311 disk. The 2314 pack was probably too heavy to use for all the repeated takes the photographer wanted. 😊

12 months

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RM 380Z software.

by jake utley

I have recently been able to fix my early 380Z blue case however it is a cassette only system and it’s not as simple as adding my spare disk controller so I’m on the lookout for 380 software cassettes or dumps of those cassettes so I can run software on it and demonstrate it at VCF Zurich in January

1 year

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RSX11M installation on real PDP11

by Peter Ekstrom

Hello to the group, I have acquired some boards and a backplane for a PDP 11/23+. The disk controller is an RQDX3 and I have a 3.5" drive that works as an RX50. I have a greazeweasle so I am able to write RX50 images to 3.5 inch floppies. I also have an RD32 MFM drive that also works. Since I have an M8189 CPU board, I have a second serial port that works as a TU58 device so I can use the tu58em emulator. I also have 512K of memory and a DZV11. Using the TU58 emulator I have been able to get RT-11 up and running on it. My goal though is to try and get RSX11M (I have no FPP right now) on it, but I am somewhat at a loss on how to get it installed. Anyone have any suggestions on how I could do that? I have some .tap files and some RL02 images with various versions of RSX11M, but I don't know how to get them onto my RD32 drive. Thanks in advance for any pointers or suggestions. And let me just say I love finally having a real PDP11!! -Peter

1 year

4
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CDC Cyber 180/8xx PSU

by hupfadekroua

Hi all, after approx 30 years of waiting our time has come to get hands on a Cyber 180/860a. These systems as other systems before are using 400Hz psus. One approach would be to use a 50Hz/400Hz power converter. There are ones on the market creating almost pure sinus output with minimal harmonics. Another approach would be to substitute the old psu by modern ones, possibly by DC-DC converters or switching powersupplies. Does someone have experience in the substitution of psus in the multiple KW range or did this in the past? Best Andreas

1 year

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