Re: CFFA Card max size for CF Card

[pausch@saaf.se (Paul Schlyter)]

In article <1147962135.573688.260250@j55g2000cwa.googlegroups.com>,
PZ <skierpaul@yahoo.com> wrote:

>Some patched versions of DOS 3.3 were capable of 400k partitions.

There was really no need to path DOS 3.3 -- it was perfectly capable of
handling 400K DOS disks the way it was written.  OK, the RWTS had to be
patched (or replaced) in order to handle physical disks of that size.
And the format command had to be patched so it produced the correct size
info in the VTOC of the disk, and so it formatted and wrote empty sectors
over the whole disk.  But apart from that, no patching of DOS needed to
be done.

Btw the 400K size limit of an Apple DOS 3.3 disk (or partition) was set
by the sector allocation map in the VTOC, which could only span one
single sector.  If the VTOC had been allowed to span any number of
sectors (like the track/sector lists could do), then the next size
limit of Apple DOS would have been set by the track and sector number,
which each had to fit within one byte, yielding a maximum disk
volume size of 256*256*256 = 16777216 bytes = 16 MBytes.  Of course
the maximum size of binary and Basic files would still be 64 kBytes
(since the file length was encoded in 2 bytes at the start of the file),
but text files should have been able to grow much larger than that.

Btw the size limit of text files under Apple DOS 3.2 was a mere
32 kBytes - which once caused me some trouble.  In DOS 3.3 this
was changed, and text files could there span the entire disk.

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