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Re: [midatlanticretro] VAX 780 vs. 750

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  • Brian Schenkenberger, VAXman-
    ... I don t think one should consider racking a VAX 11/750. ;) A VAX 11/750 cabinet was about the size of an apartment clothes washer! -- VAXman- A Bored
    Message 1 of 14 , Jul 1 12:10 PM
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      David Riley <fraveydank@...> writes:

      >On Jul 1, 2013, at 2:45 PM, Evan Koblentz wrote:
      >
      >> >> I've never actually seen any in the flesh
      >>=20
      >> Didn't I show you our storage area at the last workshop? Our 750 is in th=
      >ere.
      >
      >You did. I don't remember seeing the 11/750, but it's probably
      >because there was so much to take in that I couldn't remember
      >it all. It was pretty well organized by the time I got there,
      >though!
      >
      >Either way, I really meant I've never seen one *operating* in
      >the flesh, though I suppose that's not as material to how much
      >rack space it takes up.

      I don't think one should consider "racking" a VAX 11/750. ;)

      A VAX 11/750 cabinet was about the size of an apartment clothes washer!

      --
      VAXman- A Bored Certified VMS Kernel Mode Hacker VAXman(at)TMESIS(dot)ORG

      Well I speak to machines with the voice of humanity.
    • Dave McGuire
      ... The 11/730 s implementation of the VAX instruction set is more heavily based in microcode than that of the 11/750, making it much smaller and much slower.
      Message 2 of 14 , Jul 1 12:13 PM
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        On 07/01/2013 02:41 PM, David Riley wrote:
        > The 11/750 was a smaller, slower, cost-reduced version of the 11/780. The
        > 11/730 (even later), was a smaller, even slower, further cost-reduced version
        > of the same. My recollection is that most of the size and cost reduction was
        > accomplished by using more highly integrated gate arrays to replace discrete
        > TTL logic chips (which, at the time, were faster than the gate arrays).
        >
        > I believe the 11/730 was small enough to be easily rack-mountable, while the
        > 11/750 occupies most of a short cabinet. I could be misremembering, though;
        > I've never actually seen any in the flesh (part of why I'm excited for the
        > workshop).

        The 11/730's implementation of the VAX instruction set is more
        heavily based in microcode than that of the 11/750, making it much
        smaller and much slower. Basically fewer and fewer functions
        implemented in hardware, more and more functions implemented in microcode.

        The 11/730 CPU is built from Am2901 bit-slice chips. The control
        store (where microcode lives) is actually RAM, so when the 11/730 is
        powered up, it doesn't speak the VAX instruction set. Microcode is
        loaded from a TU58 tape cartridge into the control store by an
        8085-based service processor within the machine.

        Most 11/730 CPUs are in BA11-K style chassis, VERY compact by VAX
        standards of the day. Standard 19" rackmount.

        The VAX-11/725 is an 11/730 repackaged into a roll-around deskside
        chassis. The VAX-11/751 is a repackaged 11/750 that can be mounted in a
        standard 19" rack. The 751 was targeted at embedded and OEM applications.

        -Dave

        --
        Dave McGuire, AK4HZ
        New Kensington, PA
      • Evan Koblentz
        ... Then we have no way to run it ... yet. :( It s possible that InfoAge s big temporary generator could make 3-phase. I do not know. I ll have to ask
        Message 3 of 14 , Jul 1 12:14 PM
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          >> FYI, Evan, you'll need 208V 3-phase for the 11/780

          Then we have no way to run it ... yet. :(

          It's possible that InfoAge's big temporary generator could make 3-phase. I do not know. I'll have to ask Fred/Steve and get oodles of permission.
        • Dave McGuire
          ... I would not attempt that. No matter how good a temporary generator is, they are still much riskier than permanently-wired utility power in terms of
          Message 4 of 14 , Jul 1 12:16 PM
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            On 07/01/2013 03:14 PM, Evan Koblentz wrote:
            >>> FYI, Evan, you'll need 208V 3-phase for the 11/780
            >
            > Then we have no way to run it ... yet. :(
            >
            > It's possible that InfoAge's big temporary generator could make
            > 3-phase. I do not know. I'll have to ask Fred/Steve and get oodles of
            > permission.

            I would not attempt that. No matter how "good" a temporary generator
            is, they are still much riskier than permanently-wired "utility" power
            in terms of power quality, harmonic distortion, frequency stability,
            etc. I would not EVER risk a machine like an 11/780 on temporary power.
            Ever. I strongly advise against attempting it until your primary
            utility power is restored.

            -Dave

            --
            Dave McGuire, AK4HZ
            New Kensington, PA
          • David Comley
            If there s room for one more, I have been thinking about putting my 11/750 on my small trailer and bringing it down to the August workshop. Might be useful to
            Message 5 of 14 , Jul 1 12:24 PM
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              If there's room for one more, I have been thinking about putting my 11/750 on my small trailer and bringing it down to the August workshop. Might be useful to have two machines side by side to work on - and mine's mostly functional at this point (at least it was earlier this year).

              I have cables and odds and ends set up to boot the TU58 diagnostic tape images off my laptop if we get to that point, plus an RDM board for diagnostics.

              -Dave (C).


              From: David Riley <fraveydank@...>
              To: midatlanticretro@yahoogroups.com
              Sent: Monday, July 1, 2013 2:54 PM
              Subject: Re: [midatlanticretro] VAX 780 vs. 750

              Either way, I really meant I've never seen one *operating* in
              the flesh, though I suppose that's not as material to how much
              rack space it takes up.

              - Dave



            • Cory Smelosky
              ... I m gonna need to get out to the August workshop if that s gonna happen! ... -- Cory Smelosky http://gewt.net Personal stuff http://gimme-sympathy.org
              Message 6 of 14 , Jul 1 12:25 PM
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                On Mon, 1 Jul 2013, David Comley wrote:

                > If there's room for one more, I have been thinking about putting my 11/750 on my small trailer and bringing it down to the August workshop. Might be useful to have two machines side by side to work on - and mine's mostly functional at this point (at least it was earlier this year).
                >

                I'm gonna need to get out to the August workshop if that's gonna happen!

                >
                > I have cables and odds and ends set up to boot the TU58 diagnostic tape images off my laptop if we get to that point, plus an RDM board for diagnostics.
                >
                >
                > -Dave (C).
                >
                >
                >
                > ________________________________
                > From: David Riley <fraveydank@...>
                > To: midatlanticretro@yahoogroups.com
                > Sent: Monday, July 1, 2013 2:54 PM
                > Subject: Re: [midatlanticretro] VAX 780 vs. 750
                >
                >
                >
                > Either way, I really meant I've never seen one *operating* in
                > the flesh, though I suppose that's not as material to how much
                > rack space it takes up.
                >
                > - Dave
                >
                >
                >

                --
                Cory Smelosky
                http://gewt.net Personal stuff
                http://gimme-sympathy.org Projects
              • tedheadster
                I expect I can have an OS disk and controller pre-loaded and ready to go for any VAX-11/750 that show up. This is all thanks to the beauty of the SIMH VAX
                Message 7 of 14 , Jul 1 12:29 PM
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                  I expect I can have an OS disk and controller pre-loaded and ready to go for any VAX-11/750 that show up. This is all thanks to the beauty of the SIMH VAX simulator.

                  I build it on the simulator (runs _really_ fast), and then I just dump the finished bits onto a physical disk when done. That's what I did for both my PDP-11 and MicroVAX recently.

                  So don't sweat the software part, let's focus on getting the hardware working.

                  - Matthew

                • David Comley
                  ... Sounds like a good plan. I m sure there will be challenges aplenty. Does anyone know how the MARCH 11/750 is equipped in terms of disk storage ? UDA50 or
                  Message 8 of 14 , Jul 1 12:53 PM
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                    From: tedheadster <whiteheadm@...>
                    To: midatlanticretro@yahoogroups.com
                    Sent: Monday, July 1, 2013 3:29 PM
                    Subject: Re: [midatlanticretro] VAX 780 vs. 750

                     So don't sweat the software part, let's focus on getting the hardware working.
                    Sounds like a good plan. I'm sure there will be challenges aplenty.

                    Does anyone know how the MARCH 11/750 is equipped in terms of disk storage ? UDA50 or other ?

                    -Dave

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