On Tue, 10 Feb 2004, Patrick Finnegan wrote:
> Found some "semi-interesting" machines this week:
> - IBM PC/AT with all IBM components, nearly pristine shape excluding
> some scratches on the bottom; only missing a couple of screws and the
> hard drive. It's got the real-deal IBM 5.25" floppy and 3.5" floppy
> drives
> (1200KB/DSHD and 720KB/DSDD, right?)
Definite MAYBE
The AT was available with "1.2M" OR "360K" 5.25, but the 1.2M is by far
the more common choice.
Telling them apart isn't always easy!
When IBM realized that differentiation was an issue, they started putting
an asterisk on the front plate of the 360K. Hmmm. Let's see. "Two
similar ones, so let's make a change in the appearance of the OLD style
one,..."
Therefore, if there is an asterisk then it is 360K.
If there is NO asterisk, then it is either a 1.2M, or an older 360K,
or a different brand of 360K, ...
If they had put the identifier on the NEW type, then it would have been
possible to have consistency.
NEITHER 720K, NOR 1.4M 3.5" drives were out when the AT was introduced.
LATER, (with DOS 3.20), 720K was introduced, and became available
as an option for the AT.
LATER, (with DOS 3.30), 1.4M was introduced, and became available
as an option for the AT. But the PS/2 was ALSO introduced then, so
instead of adding a 1.4M to an AT, many "power users" switched to PS/2
instead.
--
Grumpy Ol' Fred cisin_at_xenosoft.com
Received on Tue Feb 10 2004 - 13:43:19 GMT