On Tue, 18 Apr 2017, dwight via cctalk wrote:
Some times it reads part of the disk. I don't know
what it is looking at
but it won't format over some types of original data. I've often erased
with supper magnet to get past such stuff.
That really got silly when they added "UNFORMAT"!
It may also be that is just doesn't support 77 and
can only do 80 tracks.
SOME version used to. Not any more.
In the very early days, you could buy MS-DOS on 8"!