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34446Re: [midatlanticretro] MARCH's 11/44

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  • David Riley
    Feb 17, 2014
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      On Feb 16, 2014, at 11:42 PM, Dave McGuire <Mcguire@...> wrote:

      > On 02/16/2014 11:16 PM, Evan Koblentz wrote:
      >>>> Humor me. What are the possible commands (and what do they do / what do
      >>>> they return) in firmware mode?
      >>>
      >>> In this manual:
      >>>
      >>> http://bitsavers.trailing-edge.com/pdf/dec/pdp11/1144/1144_UsersGuide.pdf
      >>>
      >>> ...see section 2.2, "Console Commands", starting on page 2-4. (PDF
      >>> page 33). It's a simple pseudo-front-panel monitor program...you can
      >>> deposit data into memory, examine data in memory, execute from a
      >>> specified address, execute a bootstrap for a particular device, etc.
      >>>
      >>> Note that all numbers (in all of PDP-11 land, not just here) are in
      >>> octal notation.
      >>
      >> I see your point. Even the self-test looks pretty dull.
      >
      > Yeah. When you're at the ">>>" prompt, you're interacting with
      > firmware running on an 8085 that has direct access to parts of the
      > PDP-11/44's internal CPU bus, as well as the Unibus. That 8085 has 4KB
      > of ROM and 256 bytes of RAM, on a very crowded board, and with all the
      > bus control stuff going on, they'd have been hard-pressed to get much
      > more functionality out of that.

      Yup. We did get it to boot Unix successfully off of Matthew's Emulex
      SCSI card, but that's back with him now. There are RL drives with the
      machine (I think their cables are even still attached), but I don't
      think they're in the rack. There's an RA60 which we didn't have any
      media to test with (and any of the other RA drives were tripping the
      breaker on the generator as soon as we powered them up; we need a
      fatter power feed for this machine).

      Theoretically, one of the RA drives might be bootable. However, my
      recollection is that it's an RA80 and an RA92, so they may be a bit
      balky even if we could keep them on without tripping breakers.

      I'd like to work to get this machine up and running, but it's really
      challenging for me to get out right now; my wife works most weekends,
      and my 2.5-year-old isn't as good with a screwdriver as I'd like her
      to be yet. I hope we can make it happen soon.


      - Dave
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