Dave Dunfields IMD program - CP/M

This is a discussion on Dave Dunfields IMD program - CP/M ; Hi all, sorry for this (silly) question: How can I rewrite an .IMD file to a floppy? Yes I read the manual, but I seem to miss something. Please no flames! Thanks, Uwe....

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  1. Dave Dunfields IMD program

    Hi all,

    sorry for this (silly) question: How can I
    rewrite an .IMD file to a floppy? Yes I read
    the manual, but I seem to miss something. Please
    no flames!

    Thanks,

    Uwe.

  2. Re: Dave Dunfields IMD program

    > sorry for this (silly) question: How can I
    >rewrite an .IMD file to a floppy? Yes I read
    >the manual, but I seem to miss something. Please
    >no flames!


    It's really not that hard, although there are a couple of
    things you need to know about the image and the drive
    you plan to write it back on.

    You need to set double-steppng either ON or OFF,
    this will depend on the type of drive the image was
    recorded on and the type of drive you write it on.

    In general, if the image contains 40 cylinders (you can
    tell this with IMDU) and your drive has 80 cylinders
    (5.25" HD or 720k drive) then you will need to turn
    double-step ON, otherwise leave it OFF.

    If the drive you plan to write it on is a different speed
    than the one the image was recorded on, you may
    need to set a data rate translation. The most common
    times you need to do this are if a double-density image
    was recorded on a HD drive (300kbps) and you are
    planning to write it back to a DD drive - in this case,
    set a data rate translation of 300->250

    Conversly, if the image was read on a DD drive and
    you are planning to write it back to an HD drive, you
    may need a 250->300 rate translation (and most likely
    double stepping).

    NOTE: The data rate that the image was recorded at can
    be determined with IMDU.

    Once you have worked out the setting you need, press
    'W' to write the disk, select the file and IMD should write
    the disk.

    Note that many PC systems cannot write single-density
    and may have issues with some of the more oddball
    double-density formats that exist.

    Reading/Writing diskette images is more complex than
    you might think given the variety of different drives and
    formats that exist - I've put a great deal of information into
    the IMD help file to try to describe the issues, and it's
    worth spending the time to really understand this if you
    want to archive and recreate arbitrary disks successfully.
    If you have specific questions about this information, this
    is probably as good a place to ask as any.

    Dave

    --
    dave06a@ Low-cost firmware development tools: www.dunfield.com
    dunfield. Classic computer collection: www.classiccmp.org/dunfield
    com


  3. Re: Dave Dunfields IMD program

    Dave Dunfield wrote:
    >> sorry for this (silly) question: How can I
    >> rewrite an .IMD file to a floppy? Yes I read
    >> the manual, but I seem to miss something. Please
    >> no flames!

    >
    > It's really not that hard, although there are a couple of
    > things you need to know about the image and the drive
    > you plan to write it back on.
    >
    > You need to set double-steppng either ON or OFF,
    > this will depend on the type of drive the image was
    > recorded on and the type of drive you write it on.
    >
    > In general, if the image contains 40 cylinders (you can
    > tell this with IMDU) and your drive has 80 cylinders
    > (5.25" HD or 720k drive) then you will need to turn
    > double-step ON, otherwise leave it OFF.
    >
    > If the drive you plan to write it on is a different speed
    > than the one the image was recorded on, you may
    > need to set a data rate translation. The most common
    > times you need to do this are if a double-density image
    > was recorded on a HD drive (300kbps) and you are
    > planning to write it back to a DD drive - in this case,
    > set a data rate translation of 300->250
    >
    > Conversly, if the image was read on a DD drive and
    > you are planning to write it back to an HD drive, you
    > may need a 250->300 rate translation (and most likely
    > double stepping).
    >
    > NOTE: The data rate that the image was recorded at can
    > be determined with IMDU.
    >
    > Once you have worked out the setting you need, press
    > 'W' to write the disk, select the file and IMD should write
    > the disk.
    >
    > Note that many PC systems cannot write single-density
    > and may have issues with some of the more oddball
    > double-density formats that exist.
    >
    > Reading/Writing diskette images is more complex than
    > you might think given the variety of different drives and
    > formats that exist - I've put a great deal of information into
    > the IMD help file to try to describe the issues, and it's
    > worth spending the time to really understand this if you
    > want to archive and recreate arbitrary disks successfully.
    > If you have specific questions about this information, this
    > is probably as good a place to ask as any.
    >
    > Dave
    >
    > --
    > dave06a@ Low-cost firmware development tools: www.dunfield.com
    > dunfield. Classic computer collection: www.classiccmp.org/dunfield
    > com
    >

    Hi Dave,

    thanks for your hints (especially to use IMDU)! I now know that the
    image is an 8" image. I then was able to copy the image back and using
    SYBEX 22DISK programm I could extract the files.

    Thanks again,

    Uwe.

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