Re: Apple2 disk controller questions

[supertimer@aol.com (Supertimer)]

"Fabrice Frances" <frances@ensica.NOSPAM.fr> wrote:

>- Apple][ disks are FM encoded, right ?

Actually, Apple II disks are GCR encoded.  The 5.25" ones
are single sided, double density.  That's why they store only
144k, a little less than half of a double sided, double density
DOS FAT 5.25" disk (320k).  Apple II double sided, double
density 3.5" disks are also GCR (800k).  Apple II double
sided, double density disks are MFM (1.44MB).

GCR is no less efficient than MFM, unlike FM which is less
efficient.  In fact, Apple II and Macs squish 800k into a disk
that Win/DOS PCs format to 720k!