ST-506
<storage> The first full-height 5.25 inch {hard disk drive}
for {personal computers}, introduced in 1980 by Shugart
Technology (now {Seagate Technology}). The ST-506 stored up
to 5 {megabtyes} after {formatting} using {MFM encoding}. It
transferred data at 625 {kilobytes per second}.
The ST-506 (like the {ST-412}) was interfaced to a computer
via a {disk controller}. The interface was a faster version
of the Shugart Associates {SA1000} interface, which was in
turn based upon the {floppy disk drive} interface. Two cables
connected the controller to the disk. The 34-pin control
cable controlled mechanical motion and data was read or
written serially using two pins of the 20-pin data cable.
Other companies copied the interface, creating a universal {de
facto standard} that was further strengthened by its revision
to support Seagate's 10 MB ST-412 drive that was adopted for
the {IBM PC XT}.
Around 1990, {SCSI} and {ATA} superseded ST-506. These
eliminated the problems of matching controllers to drives by
physically integrating a controller with the drive, allowing
{interleave ratios} and other disk parameters to be optimised
by the manufacturer rather than the system integrator.
Connector pin-out (http://www.gamesx.com/hwb/co_ST506.html).
(2007-03-06)