3" floppy disks

3-inch floppy disks had its time in computer market, especially with Amstrad CPC (or PCW) microcomputers or Sinclair. But not only, as for example there were versions of Bosman 8 with two 3" disk support.
In Poland these disks were rare but accessible, and more expensive than 3.5" media.

Because of this accessibility problems users quickly discovered that 3" drives are one-sided (you could flip a disk) and Shugart-compatible. In many computers it's possible to connect 3.5" drive instead of 3" and "flip a disk" with switch switching disk side select line in drive.

Manufacturer: different
Type: Disks
Capacity: to 800kB.

If you think about connecting 3" drive from Amstrad to a PC, you should see this page: - http://www.fvempel.nl/3pc.html - REMEMBER ABOUT ROTATING THIS POWER PLUG!!! If you plan to do it you will know. - Missing Euro.def More 22DSK-related info can be found in Robotron page.
3" drive in Amstrad CPC and detsil of 3" disk. Notice disk protection cover mechanism.