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Thread: Format compatibility between CP/M-86 and the CP/M-80s?

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    Question Format compatibility between CP/M-86 and the CP/M-80s?

    I am working to revive an old V20 laptop to run CP/M 86 since it isnt much good for anything else...

    My question to those of you who have used it... Is the '86 format more like MSDOS... and is it likely to be easy(ier) to work with '80 disk formats?

  2. #2

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    I believe CP/M-86 uses its own disk format, but don't quote me on that.

    p.s. With a NEC V20 CPU, you can also run CP/M-80, because the V20 includes Intel 8080 emulation.

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    Nope, there's no practical difference between CP/M-86 and CP/M-80 as far as disk formats go. Like CP/M 3/CP/M Plus, there are some additional dummy directory entries for date stamps, but those are ignored by CP/M 2.2 and earlier. Even CP/M 68K uses the same file system.

    Now, Concurrent DOS is a different matter--it uses the MS-DOS FAT file system.
    Last edited by Chuck(G); April 10th, 2010 at 10:32 PM.

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    Quote Originally Posted by vwestlife View Post
    I believe CP/M-86 uses its own disk format, but don't quote me on that.

    p.s. With a NEC V20 CPU, you can also run CP/M-80, because the V20 includes Intel 8080 emulation.
    I can just imagine attempting to build a BIOS for a Tandy 1510HD to run CP/M-80 + +

    Edit: Do you know of anyone who has done such a thing? Access to source code would be... interesting, at least!

    Quote Originally Posted by Chuck(G) View Post
    Nope, there's no practical difference between CP/M-86 and CP/M-80 as far as disk formats go. Like CP/M 3/CP/M Plus, there are some additional dummy directory entries for date stamps, but those are ignored by CP/M 2.2 and earlier. Even CP/M 68K uses the same file system.

    Now, Concurrent DOS is a different matter--it uses the MS-DOS FAT file system.
    Its a pity I dont have CPM+ running on the 4p... it would make the disks damn-near indistinguishable between the two!

    Thanks to both of you! Once I complete surgery on the floppy drive... presuming it is successful, I can attempt the Frankensteination of the laptop!

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    You need to understand that CP/M floppies aren't like MS-DOS floppies--there is no "standard" format, save the 8" single-density single-sided 128-byte sector version.

    At best guess, there are probably somewhere around 750 different CP/M disk formats out there and probably more. I've seen about 550 of them myself.

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    Quote Originally Posted by vwestlife View Post
    I believe CP/M-86 uses its own disk format, but don't quote me on that.

    p.s. With a NEC V20 CPU, you can also run CP/M-80, because the V20 includes Intel 8080 emulation.
    Quote Originally Posted by Chuck(G) View Post
    You need to understand that CP/M floppies aren't like MS-DOS floppies--there is no "standard" format, save the 8" single-density single-sided 128-byte sector version.

    At best guess, there are probably somewhere around 750 different CP/M disk formats out there and probably more. I've seen about 550 of them myself.
    Oh yes, Im PAINFULLY aware of that! I have also successfully 'modified' Montezuma's format(s) to properly read 'raw data' from a couple of sources. (USING that data however is yet to be...)

    Just a bit of 'pipedreaming'!

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    Yes, Kaypro even had at least six [6] different CP/M versions alone ! What a mess !

    So many today find that out when they get an inexpensive - FREE? - Kaypro, but with no disks.

    Then if the Kaypros were "modified" in some way by some of their owners, then things can get really "dicey !"

    You just have to check the chips, etc. “under the hood” to verify what you really have. Bitsavers free download Kaypro technical manuals can help.

    Of course, Kaypro in the later years when they were struggling to just survive with the incredible onslaught of Compaq, many issues in manufacturing probably occurred to further complicate matters – just what was in some of those computers that they were manufacturing ?

    If you were ever in “production,” you can appreciate what can [and often does] go
    wrong ! I was and the stories to tell – mostly “funny” and preventable !

    Guess that is why "deviceside" has not gotten into CP/M that much.

    By the way, Adam of "deviceside" just emailed me that he is adding some drivers so files converted by Uniform, that came with Kaypros and some other computers, will work better with his device.

    If you do not know, Uniform can convert CP/M files, along with many other formats from many other computers, to MS-DOS files. It will format a 5.25” floppy disk to MS-DOS and put these converted files on it. Uniform is on eBay many times for less than $5.

    My wife and I are just thrilled, since we have thousands of such floppies with a lot of our research and other work on them from the 1980’s / 1990’s.

    When I get these new drivers I will see and let you all know.

    Right now, briefly, I have found "it works as advertised" – but as some have pointed out - make sure you understand exactly what you are getting.

    Will do the requested review when all of this is finally resolved and verified.

    Frank

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    Quote Originally Posted by leeb View Post
    Oh yes, Im PAINFULLY aware of that! I have also successfully 'modified' Montezuma's format(s) to properly read 'raw data' from a couple of sources. (USING that data however is yet to be...)

    Just a bit of 'pipedreaming'!
    If you have a PeeSee that will boot DOS, you might want to consider 22DIsk...

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    Quote Originally Posted by Chuck(G) View Post
    If you have a PeeSee that will boot DOS, you might want to consider 22DIsk...
    Hey, I've chatted with the guy who wrote that; he's helped me out a few times and I think he even hangs out on this forum sometimes...
    And I think he had something to do with the 22NICE emulator too...
    Last edited by MikeS; April 11th, 2010 at 04:38 PM.

  10. #10

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    Yep. I've used 22DSK on a MS-DOS machines to stock up a Kaypro with software. The progam works well and seems to support many CP/M formats.

    Tez
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