How to use IBM SaveDskF floppy format on modern machine

Question

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.)

Answer 1

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).

Answer 2

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).