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Thread: Kaypro 10 Reinstall Disks

  1. #11

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    If you're using a 1.2 MB HD drive to write the image, you need to set IMD for 300k DD, so you get the right data rate on the Kaypro owing to the differences in spindle speed (360 RPM vs. 300 RPM).

  2. #12
    Join Date
    Oct 2014
    Location
    Pottstown, PA
    Posts
    219

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    Ah, I did not set it for 300K DD . I guess it shows I DO NOT understand what these stock kaypro 390K floppies are all about;
    it doesn't make any sense to me yet why 80 track drive comes into play.
    I was mainly trying to find a combination that didn't show errors writing out in IMD...
    to understand what the intent of the IMDs were in those files... still not expecting them
    to actually work in the stock kaypro once I built them.

    I'm following the advice of trying to rebuild the offending disks from the discrete files. If I'm successful
    then I'll reimage the new media and offer it back to the archives.

  3. #13

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    I'm late to the party, but Kaypro standard floppy drives are 40-track (48 track/inch) double sided, so a total of 80 tracks of data. However, Kaypro floppy format is a little odd as the sectors on side 0 are numbered 0-9 and on side 1 are numbered 10-19 (more common formats have both side 0 and 1 sectors numbered 1..N). Hopefully the IMD images preserve that numbering and the diskette imaging software will transfer that to the disk (requires actual formatting, not just writing sectors). Making things worse, the Kaypro directory sectors are on side 1, so no files can be read if side 1 is not formatted correctly.

    I recently created a Kaypro simulation and ran through the Kaypro 10 re-install, virtually at least. The "k10hald*" images worked for me, but I used ROM 81-302c (these images are CP/M 2.2H). I'm not sure just what ROMs are compatible with what CP/M versions, but the "universal ROM" (81-478a) was a departure and requires the CP/M boot image to be checksummed before it will boot it. I think you need CP/M 2.2u for that.

    Also, there appears to be a difference between ROM 81-302c and 81-478a "universal" in how they manage the hard disk directory. The '302c does some sort of "mirroring" of directory sectors and hides this from CP/M (artificially alters track numbers to hide it). I suspect you cannot take a hard disk created on one ROM and boot with the other ROM.

    If I can be of help, let me know.

  4. #14

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    I know I'm late to the party, but the standard floppy drives used in Kaypros had 40 physical tracks (more correctly called cylinders, but most people did not use that term) and with double-sided drives that results in 80 tracks of data.

    The Kaypro floppy format was a little odd. The physical sector numbering (in the sector headers) was 0-9 on side 0 and 10-19 on side 1. In addition, the physical side byte may have been "0" on both sides, but either way Kaypro BIOS ROMs told the WD1793 to ignore the side byte. More conventional floppy formatting numbered sectors 1-N on both sides and set the side byte to 0 or 1 and included that in sector header compares. I beleive the IMD images preserve the physical header formatting, but the program to write the IMD image to floppy must also format the track accordingly. It is not sufficient, at least in the case of Kaypro floppies, to simply copy logical sector data to a new floppy.

    The early Kaypro 10s (ROM 81-302c at least) also used a special mirroring algorithm on the CP/M directory sectors of the hard drive. The ROM essentially copied each directory sector to two different tracks (heads). I would assume that was in hopes of recovering from disk failure, since the directory was the most-heavily used portion of the disk. Anyway, later ROMs (81-478a "universal" at least) did not perform that mirroring, making the hard drive layout different, and I doubt you could switch ROMs and preserve data on the hard drive.

    Kaypro also had some dependencies between ROM versions and CP/M versions. I haven't worked out the complete matrix yet, but the "universal" ROM depends on a checksum in the boot sector and so you cannot boot older CP/Ms.

    I recently created a virtual Kaypro and went through the reload procedure for a Kaypro 10 (ROM 81-302c and CP/M 2.2H). I used the "k10hald*" images as I could not get the "kay10*" images to work (the latter seem to be 2.2F and may require a different ROM). Of course, that was on well-behaved virtual hardware.

    Let me know if I can help,
    Doug

  5. #15
    Join Date
    Oct 2014
    Location
    Pottstown, PA
    Posts
    219

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    Thanks for weighing in here. Thats good work and we'll look forward to your ROM compatibility matrix.
    I need to add here that part of the problem I had with the disks turned out to
    be a failure on the IBM 360K drive JUST AS I WAS DOING THIS PROJECT...
    I didn't discover that until I tried to make some disks for a 5150 PC that weren't working right
    on that machine either.

  6. #16

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    I have at least something for the compatibility matrix started here: http://sims.durgadas.com/kaypro/kaypromodels.html

    A lot of information was gleaned from the document I found on bitsavers, "Kaypro Technical Manual 1484-F".

  7. #17
    Join Date
    Oct 2014
    Location
    Pottstown, PA
    Posts
    219

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    Nice work on those compatibility details!

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