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Is there a way to write IBM SaveDskF disk images to a floppy on a modern machine?

The floppy drive is connected via USB.

Some comment somewhere said to use WinImage, but I tried that and it said the file was not a floppy image. The Linux file command says it is.

(Also, I have tried the dd command, and the Balena Etcher image writing tool, and neither worked.)

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  • 1
    What is the image length of the file in bytes?
    – RETRAC
    Feb 23 at 17:56
  • 2
    @RETRAC that won’t reveal all that much useful information, SaveDskF files are typically compressed. Feb 23 at 21:51
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USB floppy drives only support a limited set of disk formats: 720KiB (on DD floppies only), 1440KiB (“standard” HD), and in some cases, 1232KiB (“mode 3”, the format used on X68000 systems) and 1200KiB (so that 5.25” HD images can be written).

If your images are 1440KiB images, then all that’s needed is to extract the raw sector image, and write it using cp or any other tool capable of writing to a block device (which even includes the shell). I don’t know of such a tool off-hand, but you can run LOADDSKF in an emulator to write your image to a sector image. For example, using DOSBox-X:

  • place LOADDSKF.EXE and your floppy images in a directory;
  • start DOSBox-X there;
  • mount a 1474560-byte image as a floppy: imgmount -t floppy a target.img;
  • “load” the SaveDskF image onto the “floppy”: loaddskf source.dsk a:;
  • unmount the target image: imgmount -u a.

This will produce a target.img file containing the raw sector dump, which you can then copy to your actual disk using your floppy drive, e.g. cp target.img /dev/sdX, replacing X as appropriate (on Linux; you’d use different commands on Windows).

(DOSBox’s floppy emulation isn’t good enough for LOADDSKF, but DOSBox-X’s is.)

Alternatively, using QEMU, you can avoid generating intermediary images entirely; you’ll need a proper DOS setup, including your disk images and LOADDSKF. Start QEMU with your USB floppy drive connected to the emulation’s floppy, and your DOS setup as the hard drive, then run LOADDSKF directly.

There’s no way to write non-standard SaveDskF images (e.g. XDF images) using a standard USB floppy. You’ll need to use another floppy controller (KryoFlux, Greaseweazle, FluxEngine...) and an old-school floppy drive, and find a way to convert your disk images into something that can be written using whatever controller you have — Keir Fraser’s Disk Utilities might be able to do this (I haven’t tried).

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In case of uncompressed images, you can extract them (without having to use an actual diskette) using Aaru (ex-DiscImageChef).

AFAIK there is no modern tool which handles compressed images (staring with AA 5A), but there exist DIUNPACK.EXE for OS/2 which supposedly handles them (available on SAC.SK).

DIUNPACK Release 3.03 01-30-96
Copyright (C) IBM Corporation 1995, 1996

Diskette Image UNPACKer: Upacks files
from a diskette image file.
Usage: diunpack [imagefile] [-options]
 -d <directory> set the target directory
 -l list files (don't unpack)
 -p prompt for copy of individual files
 -q suppress beeps
 -n never overwrite files without prompting
 -x <filename> extract file
 -j junk path info (don't maintain disk image
    directories)]

OS/2 console programs can be run under Windows NT or Windows 2000 (and possibly ReactOS).

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  • @TomasBy you can confirm using Aaru via the image-info command. First two bytes are AA 5A in such images. Feb 23 at 21:30
  • @TomasBy: The file command should have said floppy image data (IBM SaveDskF, compressed) if they are, but you didn’t mention that in the question. Feb 23 at 21:34
  • They are compressed.
    – Tomas By
    Feb 23 at 21:35
  • @TomasBy In that case you'll probably have to either run DIUNPACK.EXE or use LOADDSKF under DosBox-X as described by Stephen. Feb 23 at 21:48
  • QEMU sounds slightly easier.
    – Tomas By
    Feb 23 at 21:50
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You can use loaddskf and savedskf on a modern computer. If you have an emulated floppy disk, you can unpack and pack diskettes to/from that. Note however, that these are bound applications, and it is best to open a command.com or 4dos session here.

For example, I use vfd.exe etc, to create a drive b:

loaddskf %1 b:
savedskf b: %2 /d /a

You then set b: to the right side, and you can convert disks to native image without having to use real floppies or a floppy disk.

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  • The thing is that under windows vista +, it might be fairly difficult to write from loaddskf to floppy directly. and you may need to image it first, and use the image in a different proggie. Jul 28 at 8:44

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