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

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  • David Gesswein
    ... If you pull the front bezel you can see the switches. The normal problem is the little plastic nubs are broken. You can repair that. 8/E switches are
    Message 1 of 91 , May 20, 2013
      >
      > Speaking of switches, the SW handle is completely broken, and 0, 1 and 2 of
      > the address/data switches also are touchy. 0 feels as though it's busted and
      > can be moved horizontally, and makes bad noises when switching up and down.
      >
      If you pull the front bezel you can see the switches. The normal problem is the
      little plastic nubs are broken. You can repair that. 8/E switches are similar.
      http://www.pdp8online.com/straight8/front_panel_restore.shtml

      > Are replacement switches as hard to find as I'd think they'd be? I'd
      > probably
      >
      I saw some of the switches recently though they are normally ok. The handles
      are harder. I have a few
      reproduction handles left. They will not match your colors properly so any
      switch handle you can fix your better of with that. If you have some that
      are hopeless email me direct and we can discuss. Some people have painted
      handles to match better.

      > I'm really looking forward to hearing some "real music"! And no, I don't
      > have a PC04 or 05, unfortunately. I do have a Facit 4047 punch/reader, and
      > since it's RS-232, I could potentially use that via the serial card. Are
      > these high speed tape readers hard to find?
      >
      You could do that or since you have the controller you could use a
      microcontroller to convert the parallel data from the controller to serial
      for your 4047. The DEC ones aren't common and tend to be expensive when
      they show up.

      > I have several 8" floppy drives. A few are DSDD, and a few are SSSD, I
      > think. What does it take to get one of these properly interfaced?
      >
      I have not heard of any controller that directly interfaced to them. Both
      the DEC and DSD used controller boards in the drive unit and a funny serial
      interface from the controller in the PDP-8 to the controller in the drive.
      The DEC drives show up reasonably often. The controller doesn't show up that
      often.
    • 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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