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Re: [midatlanticretro] Acquired a PDP-8/E

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  • Dave McGuire
    ... Congrats on your new acquisition! That s one of my favorite machines. That one appears to be in pretty good shape, with the exception of HANDWRITING on
    Message 1 of 91 , May 19 9:55 PM
      On 05/17/2013 09:27 PM, Kyle Owen wrote:
      > A friend of mine has semi-permanently lent me a PDP-8/E. It's in pretty good
      > shape, but the key is missing. It seems to have 8k of core, a high-speed
      > paper tape interface, a serial interface, and several other cards. I'm a bit
      > confused on where to go from here, though. I suppose I need to track down a
      > key. I'd also love to get a Model 33 teletype, but I think I'll make a
      > working current loop converter first. I'd like to make some music with it via
      > an AM radio, but I wouldn't quite know where to begin.
      >
      > Here are some pictures: http://imgur.com/a/6CtZi
      >
      > Any tips?

      Congrats on your new acquisition! That's one of my favorite machines.
      That one appears to be in pretty good shape, with the exception of
      HANDWRITING on the switch handles. WTF?! Can you remove that?

      First, find out how long it's been since it was last powered up. If it has
      been more than a few years, you may need to give the power supply some
      attention. If it was more recent than that, then at least disconnect the
      power supply from the backplane(s) to do a voltage check first. PDP-8/e
      boards are all 7400-series TTL logic which is available pretty much anywhere,
      but you still don't want to fry one. ;)

      Next, take an inventory of the boards. You can look 'em up to see what
      they are, or just post them and I (or someone) will identify them for you.
      (we'll want to know what it's got anyway! ;))

      Next, you'll need to hot-wire the switch until I (or someone) can send you
      a key. You don't need to literally hot-wire it; you can just remove the
      switch mechanism from the lock and turn its shaft by hand.

      When you get that far, shoot an email back to the list and we'll go from
      there...either I, Dave G, or possibly Bill D will be able to help you out.
      (among others I'm sure!)

      And once again, congrats! The 8/e is a really nice system...I'm sure
      you'll love it!

      -Dave

      --
      Dave McGuire, AK4HZ
      New Kensington, PA
    • Dave McGuire
      ... OS/8 needs a random-access storage device; paper tape won t do it. Magnetic tape drives are *physically* sequential-access, of course, but the TU56 (for
      Message 91 of 91 , Jun 6, 2013
        On 06/06/2013 12:54 PM, Kyle Owen wrote:
        > That looks like a nice product, but yes, it's certainly expensive. I've got
        > some FPGA background myself, along with several different microcontrollers,
        > so I may see about creating something that will work with my high-speed paper
        > tape interface. That could be considered an OS/8 storage device, yes?

        OS/8 needs a random-access storage device; paper tape won't do it.
        Magnetic tape drives are *physically* sequential-access, of course, but the
        TU56 (for example) is logically a random-access, block-oriented device. (with
        highly variable latency ;))

        > I would
        > have no idea how to go about writing a driver for it yet, but perhaps it'd be
        > in my best interest to start reading up on the commands for the card and then
        > learn more about OS/8. Do you have any suggestions on recommended reading for
        > this?

        If this was a generally-directed question...The book you want for "most
        things OS/8" is the "OS/8 Handbook". It is excellent. Try to find a paper
        copy if you can, but it's available in PDF on bitsavers:

        http://bitsavers.trailing-edge.com/pdf/dec/pdp8/os8/OS8_Handbook_Apr1974.pdf

        -Dave

        --
        Dave McGuire, AK4HZ
        New Kensington, PA
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