Requires

Amiga

How this works

A long time ago I found a device called "fmsdisk.device" on Aminet. It allowed you to mount a file on your harddisk as a regular floppy disk. You could then use this new drive exactly like DF0:. Unforturnately FMS often crashed on my machine upon mounting the image, and, even worse, FMS didn't allow you to swap these virtual floppies, nor did it support compressed images. Especially compressed images are very popular since the Amiga emulator UAE existed. The only way to swap a disk with FMS was to prepare another disk image and transfer it to FMS with tools like TransADF or similar. From my point of view that is neither very convenient, nor very intuitive.

DiskImage goes a slightly different way. Instead of mounting a static file you just mount the drive, eg. DI0:, and then you "insert" the disk image of your desire with a special tool. This image can be ejected at any time and replaced by another image in a way that is completely transparent to AmigaOS. DiskImage supports nearly all trackdisk commands and disk change interrupts. And even more important: it supports gzip compressed disk images via Achim Stegemann's free zlib.library. Additionally you are not limited to images from floppy disks, but you can use image files from any device you can imagine. It is even possible to dump your whole harddisk to a file and then mount this file as a mirror of your harddisk. The only limitation is AmigaDOS's limit on the size of a file, which is 2GB minus 2 bytes (= 2,147,483,646 bytes). One big advantage is the ability to mount CD-ROM ISO image files. That means if your CD writer is not able to write to CD-RW disks (ok, all recent writers are able to do that) or you don't have a CD-RW disk at hand, then you simply create an ISO image with MakeCD and mount this image via diskimage.device.