800k format readable on a real Mac?
You can format a low density (i.e. 880k) floppy under Shapeshifter in a compatible format that a Macintosh can read and write. What you can't do is the opposite, i.e. read a low density floppy, formatted on a Mac, on Shapeshifter.
Shapeshifter runs on Workbench 3.0+, so you can do this both under 3.1 and 3.9.
Varthall
