IIRC, you could no longer use 400k disks as of System
7.6, but you can
still use 800k disks up through System 9, provided of course that you
have a Mac with an internal floppy drive.
I can't reliably read or write 800K disks in my PM 6500 with OS 9.0.4.
Haven't been able to for a few OS versions. Also can't in my PM 9600. It
attempts it, and is sometimes works for reading an 800K disk. It can also
on occasion write to 800K disks, but it can never format them. It will
attempt a format, it will even complete it without complaint... but the
disk will be undreadable in machines running older OS versions. If I
format in an older machine, I can then get a few writes to the disk
before the data is unreadable in an older machine (and if the disk is
freshly formatted, then I can usually get one or two reads as well).
So based on personal experience, I just chalk it up that Apple stopped
letting you do both 400 and 800 (with 400 being right out)
Why Apple stopped
offering floppy drives, I don't know.
Cost cutting. They were trying to get the iMac down to as cheap a build
as possible, and they knew that most consumers would have little need for
a floppy drive in the long run. So it was a place to shave a few bucks
off the manufacturing costs. Alas when they choose to do it, it was still
a tad premature, as yes, in the LONG run, most consumers wouldn't need a
floppy drive... but until they migrated their entire collection of old
disks to something else, then they still needed it (but its a typical
catch-22... if Apple left the drive in, no consumer would migrate their
stuff in anticipation for the removal of the drive, so the consumer
wasn't going to stop needing the drive, until right after the drive was
no longer there)
-chris
<http://www.mythtech.net>