Five and quarter drives

From: Randy McLaughlin <>
Date: Fri Feb 11 19:27:05 2005

From: "Eric Smith" <>
Sent: Friday, February 11, 2005 7:02 PM
> Randy wrote:
>> When the PC-AT first came out there were two different types of 1.2M
>> drives:
>> 360RPM using 600K transfer rate & 300RPM using 500K transfer rate.
> Neither of those were used by the AT, and they would not be compatible
> with the AT HD disk format.
>> Gets confusing doesn't it?
> Yes.
> The AT used 500 Kbps at 360 RPM for HD mode. If IBM had used
> 300 RPM for high-density drives (which they didn't), they would
> have had to use 416 Kbps to get the same on-disk format.
> Eric

You are right, old brain cells have poor memory.

After reading, I saw that the
300RPM was for handling 360K diskettes.

Some drives like the TEAC FD55GFR that I provided a link for has a jumper to
allow for the older IBM AT controller boards that needed 300RPM drives.

Received on Fri Feb 11 2005 - 19:27:05 GMT

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