On Mon, 22 Jul 2013, Liam Proven wrote:
I have a small pile of 5.25" drives and I would
be delighted to get
rid of all of them. I don't really use such tech any more. All are
ancient PC pulls. Snag is, I don't know which ones are 80t/HD and
which 40t/DD. (1.2MB versus 360kB, to risk the wrath of Fred.)
In this context, it is completely clear what types of drives you are
referring to. Some of the many confusions in the past have involved more
obscure systems, people who refer to 40 cylinder double sided drives as
"80 track", lack of differentiation between 96tpi DD and 96tpi "HD",
To do "360K" with a "1.2M" drive requires EITHER:
drive switchable between 360RPM and 300RPM
FDC capable of a 300K sata transfer rate to compensate for the 360RPM
I'm glad that Liam stepped forward! My boxes of drives are not easily
accessible, other than one apparently new but untested drive in one of the
boxes of books.
Since these are PC (or more likely PC/AT) pulls, we can assume that few,
if any, are 96tpi DD (aka "720K 5.25"). If they are "half-height",
there are probably no single sided, etc.
Do any of them have a star/asterisk embossed on the faceplate?
If so, then those are fairly recent 40t/DD
WHen IBM introduced their 1.2M drive, they realized that they needed to
label the two types. But, being rather less than clueless, they chose to
label the wrong one. A special mark on 1.2M would have solved/prevented
the problem. Instead, they marked drives for which there already existed,
even from their own factories, MANY unmarked ones.
Therefore, if there is NOT a star/asterisk, then the drive is a
40t/DD from before the time of the mark,
a 40t/DD from a manufacturer that didn't go along, or
In general, the easiest ID will be by model number.
On Mon, 22 Jul 2013, Al Kossow wrote:
TEAC 55B 360K 40T
TEAC 55G 1.2M 80T HD
Here's a few more drive model numbers to check against:
TEAC 55FG 1.2M/"720K" 80T DD/HD
TEAC 55F "720k" 80T DD
501, 4851? 360K
504,4854 1.2M (I used to have an early one of those that had 50
pin edge connector, for drop-in 8" replacement)
Qumetrak-142 360K (needs SLOW stepping)
Shugart/Matsushita, . . .
455 360K 40T
465 720K 80T/DD
475 1.2M 80T HD
M16-P Bizarre 1.2M drive for XT 250K data transfer rate
This batch of numbers is mostly from NCC'83 and the like; some numbers
Grumpy Ol' Fred cisin at xenosoft.com