21 Jul
2014
21 Jul
'14
5:54 a.m.
On 07/20/2014 06:19 PM, Fred Cisin wrote:
I can't remember now, did 3.10 support logical drives? I have a feeling it
perhaps didn't, so the limit (from a DOS point of view) would have been
four primary partitions of 32MB each.
Interesting... I didn't realize that it was possible to go beyond the 2GB
limit and for things to still work - I always assumed that normal file ops
would break at that boundary, even if a >2GB filesystem was hand-crafted.
>
PC-DOS/MS-DOS 3.10 (three point ten) had a limit of 32M for a regular hard
> disk.
On 07/18/2014 10:51 PM, Fred Cisin wrote:
I think the disk could be larger, could it not (although practical maximum
for the consumer drive technology of the era was probably around 120MB)? It
was the initial FAT16 implementation that topped out at 32MB, so a drive
would have to be partitioned (and I don't recall what the limit there would
be - although I think the CHS addressing scheme topped out at 8GB,
presumably limits on the number of partitions possible would come into play
first).
Good catch; thank you.
Yes, the limit for a logical DOS Drive in 3.10 was 32M, but the physical
disk drive could be substantially larger. It was not at all uncommon to
use a 40M drive, split into 2 (or more) DOS drives. FAT16b came in
with DOS 3.31, and I think its individual partition size was
then capped at 2GB (at least assuming 512-byte sector sizes).
and almost all of the 2G limits should have been 4G, since they were a
limit of 32 bits. But, they ended up at 2G instead of 4G due to
programmers who never expected to come near such enormous limits and used
a signed, instead of an unsigned number. Because of that, most of DOS
was willing to accept the existence of a NEGATIVE 2G file or drive!