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Is there any easy way to port the UCSD-P System to a system like Micromint's SB180 ?

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    Is there any easy way to port the UCSD-P System to a system like Micromint's SB180 ?

    Yes, I know, there is also a Z80 version of the UCSD system, but even this version does not run on a Z80 machine without modifications, think about the disk format for example.
    Is there any documentation available how to adapt the UCSD system to a "foreign" system - like the Alteration Guide of CP/M 2.2 ... ?
    I am not asking about a P-interpreter, because this seems to be solved easily. I am talking about the machine specific parameter (screen, disk access, disk format etc.).

    #2
    Have you tried the CP/M hosted version of P-System? That should hide all the disk issues and allow you to get to the program that defines things like terminal capability.

    IIRC, one of the volumes had a guide to designing bootstrap code customizations but I can't locate it. http://pascal.hansotten.com/ucsd-p-system/ucsd-files/ has a file called ADAP40.ZIP which seems similar to what you might want.

    Apologies for any mistakes on my part; I never did any adapting to new hardware.

    Comment


      #3
      It seems you've found the right thing
      Inside the documentation, it is named "The full Adaptable System" (in Chapter IV.4, page 91). I would like to get a bootable UCSD system without the need for a "prebooted" CP/M.

      Comment


        #4
        Peter,

        There are multiple levels of customization available:

        1) Bind a new terminal gotxy (mainly aimed at using a different VDU connected via a serial link as the console) eg VT100, ANSI, ADM3 etc

        2) Change the disk parameters for an existing build - number of blocks, SPT, no reserved tracks

        3) Use the CP/M adaptable system. This boots CP/M you run a program to extract the CP/M bios which you can then use to create a P-system bootable disk (you only need CP/M as part of the adaptation process) This has the advantage of minimum effort though it also gives your worst performance as there is a shim layer adapting the SBIOS to the CP/M CBIOS. You can also create CP/M programs to perform block reads, writes and disk copies to help you along the way. There are 2 CP/M variants those for 8080 targets and those for Z80 targets.

        4) Use the full adaptable system and write your own custom SBIOS, primary boot PBOOT, secondary boot SBOOT, and transfer utility for the target system. Also assumes that you have a working 8" IBM3740 (250 kb FM disk, 128 byte sectors, 26spt, 77 tracks). The Adaptable system comes in 2 different formats: 494 block (247 Kb Standard Volume) and 3 volumes (each 26spt x 25 tracks) packed onto a 250 Kb 8" IBM3740 disk. You will need to write your own utility to copy the blocks from the volumes onto a target disk eg 5.25" 160Kb MFM disk.

        5) Write a new P-code interpreter for a new target CPU and hardware platform + SBIOS + PBOOT + SBOOT + utils.

        When you have finished your adaptation don't forget to run the new system through the Validation test suite.

        Hope this helps

        Peter


        Much of the above is easier if you have a working platform to develop the new code on. Most standard UCSD P-systems can process a Standard IBM3740 8" 494 block volume and packed 3 Volume versions. You also have access to working Assembler and compiler.

        Comment


          #5
          Peter,

          Take a look at the original 1979 UCSD II documentation.

          http://www.bitsavers.org/pdf/univOfCalSanDiego/
          UCSD_PASCAL_II.0_Users_Manual_Mar79.pdf

          There are
          sections on bringing up the 8080 / Z80 CP/M adaptable system. Page V

          Peter

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            #6
            The real question is does this process work for Z-system, since that's that's stock OS for the SB180. There's no reason CP/M can't run on it, but I don't know if there is, indeed, a CP/M for the SB180, and if the Z-System is compatible enough to work with UCSD.

            I'm guessing the P-System is uplifting the CP/M BIOS whole sale, stashing it away somewhere, and then loads it as part of the P-System. It wouldn't need the BDOS.

            I sure wish they would release the full sources to P-System IV.

            Comment


              #7
              If the Z-system does not run a standard CP/M 1.4 or 2.2 CBIOS then you will have to go the hard way and write the SBIOS from scratch. However, it is not that difficult, if you look at the SBIOS requirements then you will see that they are essentially based on DR CP/M cbios with some extensions.

              You need a basic console - char in /out
              block device - read sector, write sector, seek. Plus mapping physical sectors into 512 byte logical blocks.
              Some startup code.
              The remaining devices can just return 'off-line', though a printer might be useful!

              Other than reading the p-code modules in you can ignore interleave and skew on version 0.1 (they will greatly improve disk perfomance assume that v0.1 reads / writes 1 sector per revolution. When you get the interleave and track to track skew working you should be getting a whole track in either 1 or 2 revolutions, unless you are double blocking in which case it is more like 1 track in 3 or 4 revolutions.)

              When you have a basic working system you can tweak the performancwe and add extra funtionality.

              Peter

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