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    Format of Xenix ".pvh" table

    What version of Xenix are you running? I assume its one of the later Xenix 3 variants (3.2 or greater)?
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    Format of Xenix ".pvh" table

    Perfect! Thank you. I should have guessed that 0x04 was the length.
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    Format of Xenix ".pvh" table

    Version number in that position makes a lot of sense, although maybe its some sort of bit field, since 0x10/16 seems like a pretty number for something that probably didn't change all that much. I gleaned the max and min numbers from what diskutil would accept. It may be that the Xenix hd...
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    Format of Xenix ".pvh" table

    Anyone know the format of the ".pvh" table that is written to the first sector of the disk by the Xenix diskutil tool? I think I've figured out most of it. But there are a couple of fields that are still a mystery. Here's what I have so far: Byte Offset Length...
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    RK05 disk emulator development and discussion

    Wow. I'd completely forgotten that Andy wrote that.
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    RK05 disk emulator development and discussion

    You get to do that. All you need is a fixed, unique sequence of bytes, preferably placed at a known location in the file (right at the beginning is good). An 8 byte sequence is the minimum I would use in this case, since you're not really space constrained. But 4 would work. It doesn't matter...
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    Different Emulex UC07/08 versions for PDP11 and VAX ? ( UC07/08 vs. UC07/08 III )

    I have a UC07 that I have used in a QBUS PDP-11 with various CPU configurations (M8186, M8189, M8192) and in a QSUB MicroVAX (M7620 / KA650). In all cases I booted some form of BSD (2.9, 2.11 and 4.3).
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    RK05 disk emulator development and discussion

    Exactly. Although I think a hash of the header data, including the magic number, could be good as well. I bring this up because at the moment I'm busy adding support for various virtual disk container formats to my retro-fuse project. This is happening as part of my effort to support mounting...
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    RK05 disk emulator development and discussion

    I suggest including a magic number at the beginning of the file to make automatic identification easier.
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    PDP11/05 : the BERG40 external serial connector is weird

    Congrats on your new acquisition! I also found the console connector confusing when I first got my '05. To help me wrap my head around it I put together the following doc which shows the connector pin numbering and signal assignments, as seen from the back of the system...
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    PDP 11/03 running LSX with ak6dn's RX02 emulator board

    Actually, it looks like each swapped out process maintains it's size in the proc p_size field. That plus a global pointing to the first unused swap block could be used to compute the parent process's first swap block on process exit/swap-in. I have to say, I like the non-BGOPTION process model...
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    PDP 11/03 running LSX with ak6dn's RX02 emulator board

    This is interesting. I'd always assumed that swapping in LSX worked the same as in Mini-Unix (where swap space is allocated based on process id). I see now that it is, but only when BGOPTION is enabled. I wonder why the non-preemtive option (BGOPTION undefined) wasn't included in Mini-Unix.
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    PDP 11/03 running LSX with ak6dn's RX02 emulator board

    Indeed! I did just that for my demo at VCF West this year: PDP-11/05 at VCFWest 2023
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    PDP 11/03 running LSX with ak6dn's RX02 emulator board

    Nice work! I too am fascinated by early Unixes running on low-end PDPs, and the thought of what might have been had someone continued their development. In my case, I’m working with Mini-UNIX (a descendant of LSX) running on the PDP-11/05. Its definitely fun to see 50 year old computer with...
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    My new project: Foozle11 A T-11 based SBC

    How does the memory banking work? Any thought of using an MMU like the 74LS612? Probably pretty straight-forward to port Mini-Unix to it. New CF disk driver plus a new console driver should do it.
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    PDP-11/20 runs UNIX V1 with UniBone devices

    How funny! I had that *exact* thing happen to me at VCFW while showing off my 11/05 + ME11 running Mini-Unix. Worked flawlessly the first day; next day there's a stuck bit in one of the MM11s. I just disconnected the ME11 and emulated the missing 20KW. Unibone to the rescue!
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    RK05 disk emulator

    Always happy to see someone making use of my little project! (y) In my experience these cables are relatively rare. Took me quite a while to acquire the one I have, and unfortunately its not in great shape (foam lining is disintegrating). Of course with my M9042 clone I didn't really need it...
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    Terminal program that handle reader run signal?

    Are you thinking of building a custom board for this? I ask because I wonder if it could be designed to subsume the functionality of my 11/05 console adapter? E.g. provide support for both a traditional TTY connected via RS-232 or a computer connected via USB. Also it would be great if it had...
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    Terminal program that handle reader run signal?

    That would be slick. I guess you'd have to decide when to exit the send mode, in the event that the system didn't consume the entire tape. Maybe after a certain amount of time with no READER RUN signal. In this case are you thinking of a TTY with an actual paper taper reader, or a terminal...
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    Terminal program that handle reader run signal?

    Teensy 4.0/4.1 has multiple UARTs plus a USB host interface. Teensy 4.1 also includes a SD card socket. So you could set up the UARTs to pass characters back and forth between the console and the TTY by default. Then, when the user plugs in an SD card, or a USB flash drive, the system switches...
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