Re: Apple and linux question

[supertimer@aol.com (Supertimer)]

Martin Gruen <mgruen@shell.fastlane.net> wrote:

>One kink between transfering PC and the GS is the 800k disk barrier, but
>that may not be true.  About five years ago my sister was running a piece
>of software that formated floppys higher and allowed the PC to read them.
>I believe 768k disks could be formated to 800k or 1.44k even without a
>second hole being punched.
>If we could get a PC to read disks at 800k we would still need some sort
>of FST (or the equivalent) to allow it to understand what it's reading,
>correct?  Anyone up for the challenge if I can get the software?

Sadly, this will not work.

Beneath the file system (ProDOS, HFS, or MS-DOS FAT) lies the low
level encoding.  File system and low level encoding can be thought of
as two levels.

IBM double density and high density disks and Apple II/Mac high
density disks are MFM encoded.  Apple II/Mac double density disks
are GCR encoded.  IBM controllers cannot read GCR encoding.

To prove the point, the BlueDisk controller by ///SHH Systeme
allows you to format 800k ProDOS and HFS disks, but the catch
is that such disks are MFM encoded, not GCR as Apple drives use.
The result?  An 800k ProDOS disk formatted with BlueDisk can't
be read on a regular Apple II 3.5" disk drive.  It can, however, be
read on a Win/DOS PC's drive with the right software!

Similarly, the PC Transporter allows you to format using MS-DOS
FAT as a file system ON APPLE 5.25" DRIVES!  However, since
the low level encoding is GCR, not MFM, such disks can't be
read on real Win/DOS PCs.  They CAN be read on Apple 5.25"
drives on the IIGS using the MS-DOS FST, though.

Controllers let you read low level encoding.  FSTs let you read
file systems.