macintosh disks : which format for archiving ?

What is the recommended format for archiving Macintosh disks (400k, 800k) ? I hesitate between using my SCP card or using the standard DiskCopy 4.2 on a Macintosh.
I did archive several ones using DiskCopy 4.2 and then compressing the images in one Stuffit 5.5 container. The reasoning behind is that using a variable speed floppy disk drive on a Mac to create images would be more reliable than using a standard floppy disk drive and SCP. The DiskCopy / Stuffit combination allows to recreate the physical disks on a physical machine.


  • If the disk is not copy protected, then either way will "work".

    Just be sure to write protect the disks, as Macs love to write desktop information and last used dates back to the disks. Also, make sure disks are "clean" and in good condition before inserting them in to a drive - because early Macs usually used floppy as their only storage, these disks typically got a LOT of wear.

    For the purposes of posting on Winworld, I usually convert to an "IMG" raw sector image. The main reason being we needed to choose a standard, and many of our Mac archives were already in this format. Exceptions being Lisa software and a few others that may need the normally unused sector tags that IMG files exclude. (If there is ever any doubt, I will include source SCP/KF/SIT images).

    A couple of things about archiving Macintosh disks with a SCP - always select "splice" mode with at least 3 revolutions. The reason being, Macintosh 400/800k disks are not sector aligned. 1 or 2 revolutions is not enough for some decoding tools.

    In practice, when archiving Macintosh disks using a SCP, KF or other flux dumping tool, it is a very good idea to keep multiple 3.5" floppy drives around. All PC 3.5" drives must be tested ahead of time with known good 400/800k disks to ensure their analog filtering is sufficiently compatible with GCR (Teac and Toshiba drives are usually the best). In practice, when dumping weak/damaged Macintosh disks, it is all too common to have to switch drives to find one that will just read a marginally readable sector.

    You are right that a genuine Macintosh should have better results reading a disk. In practice, however, if a Macintosh disk is damaged, most of the time a genuine Mac will have problems reading it too.

    Which leads to another issue. With a Mac, reading a disk is all or nothing. If there is an error anywhere, Apple disk tools will usually stick their nose up and not give you anything.

    This is why, despite everything, I still lean toward using flux dumping tool for these disks. If that first read attempt rips up the disk, then a Mac will leave you with nothing, but a flux dumper will still give you something you can analyze later. Personally, I find the Kryoflux easier to use for this as I can easily mix and match tracks from multiple dumps.
  • edited May 10
    @SomeGuy thanks for your advice, I will then go for the SCP scan. I need to test the floppy drive, to have the best results.
    How do you check if the dump has no bad sectors ? HxC doesn’t seem to recognise the Macintosh format when I open the SCP archive.
  • I normally use the PCE tools included with the PCE emulator to decode Macintosh images.

    The Kryoflux software also supports decoding of Macintosh images, both from an existing flux stream dump or interactively directly from a disk. But most of the time the PCE tools does a better job.

    The commands to convert are:

    pfi "dump.scp" disk1.pfi
    pfi disk1.pfi -c 0-79 -p set-rpm-mac-500 -r 500000 -p decode pri disk1.pri
    pri disk1.pri -p auto-align-gcr -p decode gcr disk1.psi -f -v

    psi disk1.psi disk1.img
    psi disk1.psi -L > disk1.txt

    erase disk1.pfi
    erase disk1.pri

    Although, out of habit I often use a batch file with this older method that should produce 100% identical results:

    pfi "track00.0.raw" disk1.pfi

    pfi disk1.pfi -c 00-15 -R 2 -r 381310 -p decode pri diska.pri
    pri diska.pri -p auto-align-gcr -p decode gcr diska.psi -f -v

    pfi disk1.pfi -c 16-31 -R 2 -r 349510 -p decode pri diskb.pri
    pri diskb.pri -p auto-align-gcr -p decode gcr diskb.psi -f -v

    pfi disk1.pfi -c 32-47 -R 2 -r 317700 -p decode pri diskc.pri
    pri diskc.pri -p auto-align-gcr -p decode gcr diskc.psi -f -v

    pfi disk1.pfi -c 48-63 -R 2 -r 285950 -p decode pri diskd.pri
    pri diskd.pri -p auto-align-gcr -p decode gcr diskd.psi -f -v

    pfi disk1.pfi -c 64-79 -R 2 -r 254190 -p decode pri diske.pri
    pri diske.pri -p auto-align-gcr -p decode gcr diske.psi -f -v

    psi diska.psi -m diskb.psi -m diskc.psi -m diskd.psi -m diske.psi disk1.psi
    psi disk1.psi disk1.img
    psi disk1.psi -L > disk1.txt

    erase disk1.pfi
    erase disk1.pri
    erase diska.pri
    erase diskb.pri
    erase diskc.pri
    erase diskd.pri
    erase diske.pri
    erase diska.psi
    erase diskb.psi
    erase diskc.psi
    erase diskd.psi
    erase diske.psi
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