11 Sep
2012
11 Sep
'12
10:25 a.m.
yOn Tue, 11 Sep 2012, Alexandre Souza - Listas wrote:
Jose, if you're talking about the apple
floppies, it doesn't double to
720, but 360. The apple floppy is a 180KB disk, and not a 360 one. 360 is
what you get using both sides of the disk.
No, 280K is what you get if you use both sides of an Apple ][ diskette
(140K).
It is GCR (neither FM nor MFM) with 1 side, 13 or 16 sectors per track,
and 256 bytes per sector.
MFM 80 track single sided gives 320K to 400K, 640K to 800K when using both
sides.
To go from 360K to 720K, he is presumably using 80 track (96tpi), with
either 9 sectors per track of 512 bytes per sector, or 18 sectors per
track with 256 bytes per sector. There are numerous such formats.