Five and quarter drives

[Eric Smith]

Dwight wrote:
>  Also, not mentioned is that I believe the rotation
> rate is different for the two drive. (360/300 rpm or something)

There are two kinds of 1.2M (HD) 5.25-inch drives:

1)  Some drives use a pin on the bus to signal which motor speed
    (300 or 360 RPM) to use, so that a host can handle DD and HD disks at
    the normal 250 Kbps and 500 Kbps data rates.

2)  More commonly, the drive does a fixed 360 RPM, which means that HD
    disks use a 500 Kbps data rate, but DD uses 300 Kbps (rather than the
    normal 250 Kbps at 300 RPM).

Eric