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  1. vrs42

    What did I do to my PDP-8 today.

    Not really. The container I have is "Holloway House Quick Shine", but I suspect any mop-n=glo type product would do. Basically the idea is to get an acrylic polymer dilute enough to soak in, then dry onto all the nooks and crannies. It's also important not to use stuff (solvents) that would...
  2. vrs42

    What did I do to my PDP-8 today.

    Sintered nylon parts are definitely very porous and prone to picking up all sorts of grime. I've had some luck soaking them in "floor finish" to create a finish that is less absorbent and easier to keep clean. Now, if JLPCB would just fix their input filters to take all correct STL files... Vince
  3. vrs42

    What did I do to my PDP-8 today.

    It's Verilog, as extracted from a TTL schematic. I can send it to you if you're still interested. Vince
  4. vrs42

    What did I do to my PDP-8 today.

    Possibly. However, doing that implies a learning curve for ModelSim, and presumes that I also fully understand how to model the Omnibus. My previous experience with ModelSim was that it was easy for me to get models to simulate, but hard to get models that actually ran on the hardware. I can...
  5. vrs42

    What did I do to my PDP-8 today.

    There are three designs I need to debug, which all use the same board and CPLD pin-out. The serial is fairly simple, but the extended memory control uses all 64 of the CPLD pins. I'd like to get to a single setup with the cabling and the logic alanyzer programming the same for all three, since...
  6. vrs42

    What did I do to my PDP-8 today.

    I've been trying to set up an HP1630G to look at the Omnibus. There's a fancy new memory/boot loader under there with a serial port implementation (the Atmel programmer's ribbon cable goes there). Boot and memory work fine, but not so much the serial port. Alas, I'm out of pods on the...
  7. vrs42

    PDP-8 OS handlers

    I had a DSD floppy with a DIP switch like that. It got stuck in "format a new floppy" mode and erased my boot disk (grumble). (Alas, I replaced the DIP switch a few years down the road, but now it has bit-rot in the control ROM and won't pass self-diagnostics.) Vince
  8. vrs42

    PDP-8 OS handlers

    I can see uses for such a thing, but I also think it's extremely handy to have all those RK05 images useable, and I can't see how you'd do both. Maybe a command line flag or the like, with the default partition sizes like the RK05? It's also imaginable to do "images" with more than two...
  9. vrs42

    Expanding the OS/8 device slot table size

    Alas, P?S8 isn't much like OS/8. Each system does come with a system device handler which typically supports up to 8 units. Non-system drivers are there, but there are only a couple of utilities that know how to use them, and those utilities are mostly meant for media/file format translation...
  10. vrs42

    PDP-8 Timesharing - is anyone still doing this on real hardware?

    Eagle drawings, photographs of the board, etc. can be found here: https://svn.so-much-stuff.com/svn/trunk/Eagle/projects/DEC/TSC8-75/ The CPLD version is mostly a research idea, though. Vince
  11. vrs42

    Expanding the OS/8 device slot table size

    The late Charles Lasner used to lament that unit numbers were never implemented in OS/8. Then you'd only need a slot per driver, not a slot for every unit. (There is a mostly unused place for a unit number in the driver calling convention, but it was never used that way.) Vince
  12. vrs42

    PDP-8/e case lid latch

    My Power supply side is missing the latches (and the power supply guard to keep your fingers out of there). Here's what I have for the cover bits. They sort of hook over the power supply, so that you have to spring the thing a bit to get it off. They are riveted bits of something that feels...
  13. vrs42

    PDP-8 OS handlers

    I receieved today prototype PCBs of my take on thiis. I've got a few AT1508 supposedly on the way, arriving end of week. I should be able to try something sometime next week. The board also has the 32K memory and boot loader on it. Last I checked, I can find chips for the memory section, but...
  14. vrs42

    PDP-8/e Extended Memory & Checkerboard Test trouble

    I've had several colleagues who've experienced top block failures, so I'd inspect the heck out of those, too. Bad solder, cracked traces, dirty or corroded connector pins, etc. Vince
  15. vrs42

    My quick solution for the broken trim panel brackets

    I like it! It's reasonably easy to do, uses inexpensive replaceable parts, and seems unlikely to damage the delicate cups that the buttons press into. Vince
  16. vrs42

    PDP-8/e Extended Memory & Checkerboard Test trouble

    I'd note the slots in use during failure and success, as I have seen defective and/or dirty slots before. If that's not it, I'd look at the temperature thing, as I think that's what DHKMAD was originally designed for. I'd also do the usual bit of checking the supply rails for voltage, noise...
  17. vrs42

    PDP-8/e Extended Memory & Checkerboard Test trouble

    Any of my memory boards seem to pass the other diagnostics, but only a few can pass DHKMAD, especially for an hour or two. I haven't had any particular problem with the reliability of the diagnostic itself. OTOH, when it fails it sometimes chews itself up a bit, so that it can't go on...
  18. vrs42

    PDP-8/e Extended Memory & Checkerboard Test trouble

    In a pre-Omnibus machine, I'd suspect a core thermistor. I haven't debugged Omnibus core enough to know what they do about termperature compensation, Interesting that the Lyontek SRAM is failing. I was able to pass diagnostics with a sample I bought and a later (less noisy) prototype of the...
  19. vrs42

    What did I do to my PDP-8 today.

    Try here: http://www.bitsavers.org/components/signetics/_dataBooks/1972_Signetics_Utilogic_2.pdf There was/is also a more modern replacement for the DS8640, I think, or perhaps it was only for the DS8641 (transceiver). Never seen it IRL, though. I think it was essentially invented after it's...
  20. vrs42

    Imaging RX01/02 disks on a Linux laptop.

    I'm attempting access with "anonymous" and my email address as password. I get: Timeout detected. (control connection) Connection failed. I have also tried enter and "anonymous" as password with the same result. Update: Seems to be a Windoze problem. When I try from Linux (even WSL Linux)...
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