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What is a .dsk file (DiskDup image) and how to use it?

Composed by: that-ben
On: 2019-06-07 17:05:35
Updated by: that-ben
On: 2021-04-06 17:54:14

What is a .dsk file?

A .dsk file is a DiskDup image, an exact copy (sector by sector) of a floppy disk. DSK images were a popular format for cloning or duplicating 1980's and 1990's Macintosh floppy disks.


How to use or extract DSK images contents?

DSK images are mountable and writeable/clonable onto real floppy disks.  Tough, remember that if you want to write a DSK image onto a real floppy disk using a Windows PC floppy drive, it may not work properly, because Apple floppy drives had special firmware allowing them to write an additionnal amount of kilobytes on a given floppy disk.  PC floppy disks could hold 360KB (or 720KB for double density) while Macs could hold 400KB (or 800KB for double density).

You can also mount, browse and extract files from DSK images using various disk image tools under Mac OS.  Mounting a .dsk file makes a new drive appear on your OS, effectively letting you use it as if you had the original media inserted.

DSK images can also be attached to many emulators since it was a popular floppy disk archiving format.  Namely, Mini vMac supports direct drag and drop of DSK images onto the virtual machine window.  It will mount as it were a real floppy disk on the emulated desktop.


Under Classic Mac OS (before Mac OS X)


Mac OS 8.5 to Mac OS 9.2.2: Toast 5 Titanium

Mac OS 7.1 to Mac OS 9.2.2, write .dsk to real floppy disks or mount as virtual disk: ShrinkWrap

Mac OS 6.0 to Mac OS 7.6, write .dsk to real floppy disks: DiskDup


Under Mac OS X

Use Disk Utility bundled with every Mac OS X environment: Launch Disk Utility > FILE menu > Open disk image...


Under Windows

Open it using PowerISO (altough completely useless, since extracting any old Mac file under Windows would destroy its resource fork)


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