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Thread: Honeywell 200 resurrection

  1. #121

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    I did some work on punch card data processing equipment, although not the 129 Keypunch machine. You can see that here: http://sims.durgadas.com/punchcards/ibm029.html

  2. #122
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    Very similar to the IBM 1620 and 1401, but in particular, the 1620.

    Fields and records, addressed respectively, from the low-order position and from the high-order position.

    On the 1620, there's no way to directly (or indirectly) read the P-counter, though, I suppose, it's possible to guess it by modifying instructions. The calling sequence generally looked like.

    Exit: Branch (filled in by caller)
    Entry:
    ...
    Branch to Exit

    The 1620 did have a "hidden" register that would save the location of the next instruction before a "branch and transmit" instruction was executed, but said register was operated on only by the "branch back" instruction, which made the facility useful only for a single nesting level.

    The subroutine calling method was shared by quite a number of machines, including the CDC 6000-7000 supercomputers. ("Return jump" instruction). PDP-8 certainly uses that as well.

  3. Default

    Quote Originally Posted by durgadas View Post
    I have setup a project page for my effort. http://honeywell2000.durgadas.com/ There is a download page linked from there where you can get the "jar" file for the virtual H2000. I'm still hoping to find folks that can help, with either more details on how the machines operated or with code to run.
    Cool! I'll be trying your emulators.

    Looks like the FORTRAN manual you posted (http://sebhc.durgadas.com/hw2000/doc...Compiler_D.pdf) is the next edition of the one I mentioned upthread. I have not scanned mine yet.

  4. #124

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    I should note, that the FORTRAN manual is just a redistribution from bitsavers - for convenience sake. Not a personal collection or otherwise unavailable document. Same goes for nearly all documents I post.

    Also, a disclaimer about my FORTRAN and EasyCoder emulations. Neither is a complete implementation of the respective language. I implemented enough to (hopefully) make them useful. Plus, some features require more information, that I don't yet have.

  5. Default

    Pardon my Java noobness, but when I try to run CardPunch.jar, I get the error: "Could not find the main class. Program will exit." My JRE is version 6, which came with the Arduino IDE. Am I doing it wrong?

  6. #126

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    I'm pretty sure the problem is Java version. I compiled on Java 8, but used backward-compatibility options for Java 7. Java 6 is very old. The error message is odd, and not very helpful, but I would not expect that JAR to run on Java 6. Can you get Java 7 or 8?

  7. #127
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    I have just received a scanned copy of the H200 Main Memory Setup Manual from a contact in Switzerland. This is a very useful document for me as it isn't just a field engineer's guide but the full 49 page instruction manual for setting up the memory when it is first built. Hence it's exactly what I need to ensure that I adjust the unit for optimum reliability ... if it works at all of course. That's yet to be discovered. Some of the driver boards definitely aren't working correctly at present, so it may be a while before I know.

    image010a.jpg
    Rob - http://www.honeypi.org.uk
    The Internet is a winch to get your project off the ground ... but always have a parachute handy.

  8. #128
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    I have now installed an Arduino Mega 2560 board as a temporary USB interface between the memory unit buses and a PC, so yesterday I was able to run dynamic tests on every memory location in the two magnetic core stacks to verify that they are fully functional, which they are. These stacks were salvaged from a scrap heap decades ago and were just static mementos until now. Knowing that they are in full working order is an incentive for me to get on with the project work this year. There is much more to do before I can actually store data in the memory unit but this is a positive step forward and good news.

    Before I ran the read-write tests I dumped the existing contents of the memories. Magnetic core memories retain data persistently, so there was still data present from the last time that the computer that originally contained them was used decades ago. Although the data was still readable it wasn't possible to extract any meaningful information from it. In fact it was so ingrained into the magnetic cores that it took several read-write cycles to erase it entirely. For a while I thought that the stacks were faulty, but they just needed some exercise after being inactive for so long. At my age I know how they feel sometimes, especially just after the Christmas holiday.

    A Happy New Year to all at VCF.
    Rob
    Rob - http://www.honeypi.org.uk
    The Internet is a winch to get your project off the ground ... but always have a parachute handy.

  9. #129
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    I have now completed construction of the main memory unit. During testing one of the two core memory stacks produced some erratic results, but my colleague Marcel has others in his collection and will give them to me to try out the next time that we meet up. Apart from any minor problems that might need fixing I consider this phase of the project to be finished. However, the unit will need fine tuning for optimum reliability, but that is best done when the final operating environment is in place, e.g. a proper cooling system and power supplies set at the standard voltages.

    Even though the memory unit has a digital interface it is fundamentally analogue technology. It has fifty-two Helitrim potentiometers which set the important voltages, currents and timings and also some components can be replaced to adjust other key factors such as pulse rise times. I now have a copy of the official fifty page set-up instruction manual for the unit, kindly sent to me by a contact in Switzerland, so I know what has to be done when the time comes. Hence the unit is hardly plug and play and no doubt I will spend some time making final adjustments to it.

    I am now moving on to design of the control memory and other registers. For this I will use the 1960's Honeywell ICs in my collection instead of the original high speed magnetic core memory stack. I do have one of those but don't have the circuit boards needed to operate it or their schematics and don't relish the idea of designing my own. That device was a differential magnetic memory running at four times the normal speed for a core memory, so the circuitry was critical and it was always the most likely component to fail as well as being the only relatively advanced technology in the Honeywell 200. As the machine was aimed at the bottom of the market most of its technology was relatively simple but inclusion of the high speed control memory was what gave it its outstanding operating speed. By using a stack of flip-flop ICs instead I will have a far more reliable device that can easily be designed to run at the same speed without breaking the constraint of using only 1960's Honeywell 200 technology in my design.

    I have dismantled the main memory unit now in order to add the sockets to the other half of the same backplane where the control memory will be located, so it is currently just a pile of circuit boards and a lot of wiring on the backplane.

    The project is now getting more interesting as, rather than just getting Honeywell's original circuit boards to work together as they intended, I am now designing my own solutions to the problems that they faced, albeit using only the small scale integrated circuits that they had back then with just two logic gates per chip. The functional modules of the machine will follow their original design as much as possible, but the internal design of each module will be my own. In particular, the timings of all the internal operations will be the same as in the original machine so that it will perform in exactly the same way as that did. I have to suppress the urge to build a better machine than the H200, but just building the equivalent is likely to be enough of a challenge.
    Last edited by RobS; March 8th, 2018 at 05:51 AM.
    Rob - http://www.honeypi.org.uk
    The Internet is a winch to get your project off the ground ... but always have a parachute handy.

  10. #130
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    The links and contact page on my website was entirely out of date, so I have now updated it including the links to this site and thread. That page also now contains my email address for use by anyone who prefers to contact me directly about the project. I have also added a link to the article that I wrote about the project for the Computer Conservation Society here in the UK back in 2014. You may have to refresh the page in your browser to get the up to date version.

    At present this thread still remains the sole place where I am reporting progress on the project as I haven't organised my own website to do this yet. Once I have done that I will start posting photographs there.
    Rob - http://www.honeypi.org.uk
    The Internet is a winch to get your project off the ground ... but always have a parachute handy.

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