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Thread: Disk imaging under CP/M-86?

  1. #1
    Join Date
    Oct 2016
    Illinois, USA

    Default Disk imaging under CP/M-86?

    So, I've got some images of MS-DOS 2.11 for the NEC APC I need to clone onto some physical 8" media, .IMD format and .td0 format. I have CP/M-86 bootdisks and spares, and I can freely pipe software and images to the APC with KERMIT. Do I have any options or am i just gonna have to get an adapter board so I can hook up the FDDs to a PC compatible and write the images with imagedisk?
    Last edited by MrArgent; November 13th, 2018 at 10:03 PM.

  2. #2


    A DOS Computer with your 8" Drive attached would likely be the easiest way to go, but you have other options.
    Imagedisk (IMD) requires a DOS Computer, or an Early Windows 95 or 98 Running in DOS Mode, with the proper
    Floppy Disk Controller, that passes the testing.

    1. Kryoflux will read the 8" Floppy if you attach your Floppy Drive to the Kryoflux. (highest cost option)
    2. The Supercard Pro will also read the 8" Floppy if you attach your Floppy Drive to the Supercard Pro. (lower cost option)
    3. The Catweasel will also do the job, but they are getting hard to locate. Tim Mann has software on his site for it.

    I've got a Catweasel and a Supercard Pro.


  3. #3


    Another possible option is a Linux Computer running Debian 8.x or 9.x with the CP/M Definitions that come pre-installed.

    You should be able to easily connect your 8" floppy Drive to the Linux Computer, and write the Image with the mtools,
    and fdutils packages from the Debian repository. I'm sure I can format and write a 3.5" HD 77 Track DS with the NEC format.
    I did have to add the definition in the /etc/mediaprm file, and also calibrate for the new floppy drive.

    Debian has the following NEC Formats pre-defined:
    # NEC PC-8001A - SSDD 48 tpi 5.25" - 256 x 16
    # seclen 256

    SS DD sect=16 ssize=256

    # NEC PC 8801A/8831A - DSDD 48 tpi 5.25" - 512 x 8
    # seclen 512

    DS DD sect=8

    # NEC PC 8500/8431A, Starlet - DSDD 3.5" - 256 x 16
    # seclen 256

    SS QD sect=16 ssize=256

    A definition something like this should be close.
    DS HD cyl=77 sect=26 ssize=256

    cpmtools definition:
    # NECC NEC APC CP/M-86 - DSHD 8" - 256 x 26
    diskdef necc
    seclen 256
    tracks 154
    sectrk 26
    blocksize 2048
    maxdir 256
    skew 3
    boottrk 2
    os 2.2

    Since you already have the 8" Floppy, you could boot a Debian 9.x LiveCD and install the two packages and
    test format a floppy.

    set /dev/fd0 to NECAPC

    $sudo setfdprm -p /dev/fd0 NECAPC

    Verify parameters
    $sudo getfdprm /dev/fd0

    test format
    $superformat --print-drive-deviation /dev/fd0

    /etc/driveprm will contain the deviation value.

    $superformat --superverify /dev/fd0 NECAPC
    $superformat --noverify /dev/fd0 NECAPC
    $superformat --verify_later /dev/fd0 NECAPC
    $superformat --noverify --zero-based /dev/fd0 NECAPC

    the dd command will copy an image to the floppy drive.
    $dd if=/path/to/nec/image/necapc.img of=/dev/fd0 conv=notrunc

    Imagedisk's utility td02imd will convert a *.TD0 file to a *.IMD file. IMDU will extract the .RAW image (Sector Dump) from the .IMD file.
    IMDA will give you information on the .IMD file. TESTFDC will determine what formats can be successfully handled.

    Last edited by ldkraemer; November 14th, 2018 at 06:10 PM.

  4. #4
    Join Date
    Oct 2016
    Illinois, USA


    Got myself a good disk. Second question - anyone know what the syntax is for RDCPM? I'm trying to retrieve a copy of MS-DOS kermit for the APC I had to transfer via KERMIT86, but can't seem to work out how to get any results.

  5. #5


    If you have the CP/M Image in .TD0, or .IMD format, I'm pretty sure I can extract the files from the Image with cpmtools, and then create a .zip
    file of them for you. That way you can transfer then to the MSDOS disk.


  6. #6


    The rdcpm command line appears to be:
    rdcpm source file(s) destination Floppy

    A:rdcpm B:*.* A:
    Copy all of B: to A:

    A:rdcpm B:KERMIT.* A:
    Copy B:Kermit.* to A:



  7. #7
    Join Date
    Oct 2016
    Illinois, USA


    I ultimately decided that question'd fit the 8086 board since it concerns the machine's custom DOS port specifically, but copying to CP/M-86 via KERMIT86 was the only way i could actually physically get DOS kermit on the machine since it uses 8" media and there's no BASIC interpreter provided for DOS. Unfortunately, either NEC's customized RDCPM has different syntax for 1.2MB disks or it just can't work with them...and I don't have any single-sided, 8" media handy to try.

  8. #8


    OK, on your MS-DOS 2.11 for the NEC APC, there are two files listed in the directory that is on the .IMD that I accessed.

    00001700 53 45 54 46 4C 4F 50 20 43 4F 4D 20 00 00 00 00 SETFLOP COM ....
    00001710 00 00 00 00 00 00 43 5C 3C 08 9C 00 F1 05 00 00 ......C\<.......

    00001980 52 44 43 50 4D 20 20 20 43 4F 4D 20 00 00 00 00 RDCPM COM ....
    00001990 00 00 00 00 00 00 DC 4D 85 06 05 02 50 25 00 00 .......M....P%..

    In the HEX bytes I see:
    000C4590 55 74 69 6C 69 74 79 0D 0A 53 45 54 46 4C 4F 50 Utility..SETFLOP
    000C45A0 20 20 43 4F 4D 20 20 20 20 20 31 35 32 31 20 20 COM 1521
    000C45B0 20 31 2D 32 38 2D 38 34 20 20 31 31 3A 33 34 61 1-28-84 11:34a
    000C45C0 20 20 4E 75 6D 62 65 72 20 6F 66 20 64 69 73 6B Number of disk
    000C45D0 65 74 74 65 20 64 72 69 76 65 73 20 75 74 69 6C ette drives util
    000C45E0 69 74 79 0D 0A 47 45 54 53 59 53 20 20 20 43 4F ity..GETSYS CO

    Try running the SETFLOP.COM program and make sure the Floppy's are set properly.
    There may be a help screen if you try something like

    >SETFLOP /?
    >RDCPM /?


    See if you get any help or error messages. I can't find any text in the HEX bytes that gives more information.

    Next step is to write the MD211SYS.RAW file to a 3.5" 77 Track, 8 Sectors, of 1024 Bytes, and see if I can get a directory
    listing of the files.



  9. #9



    /* Definition */
    DS HD cyl=77 sect=8 ssize=1024

    $sudo setfdprm -p /dev/fd0 NECDOS
    $sudo getfdprm /dev/fd0

    $sudo superformat --superverify /dev/fd0 NECDOS
    $sudo dd if=/path/to/MD211SYS.RAW of=/dev/fd0 conv=notrunc

    I can set the 3.5" floppy for DS, 77 Tracks, 8 Sectors per track, 1024 bytes per sector, and dd writes the .raw image correctly.
    But, the problem is that mtools doesn't see it as a MSDOS image that is recognized. So, now I'm stuck again.

    Last edited by ldkraemer; November 17th, 2018 at 01:19 PM. Reason: added info


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