The 5MB ST-506 MicroWinchester was the first 5.25" hard disk drive, introduced
in 1980 as the first product from Shugart Technology (shortly to be renamed,
Seagate Technology). The market success of the ST-506 (along with the
subsequent 10MB ST-412 and 20MB ST-225) led to the ST506 interface between
disk controller and drive (an incremental derivation from the interface for
the 8" 10MB Shugart Associates SA1000 hard disk from 1979) being established
as an industry standard for hard disk drives.
Note that with ST506 type hard disks, the disk itself is attached to a
separate disk controller unit, which in turn attaches to a host computer
At the time of the Atari, hard disks paired with ST506 type controllers were
popularly characterized not by the interface (ST506), but by the recording
method used by the controller: either modified frequency modulation (MFM) or
run-length limited (RLL).
Sold by SWP for 64KiB ATR8000 units (with CP/M) for the Atari (1986):
5MB, 10MB, or 20MB hard disk packages with SWP host adapter (40 pin header
connector to controller), WD1002-HDO MFM controller (ST506 interface: 34 pin
header drive control + 20 pin header data connectors), and "a new CP/M" with
ZCPR3 option. Can be partitioned for MYDOS & CP/M, plus MS-DOS for CO-POWER.
The SWP ATR8000 hard disk interface supports up to 32MB of hard disk storage.
Also, some hard disk "bridge" controllers allow a ST506 type hard disk to be
attached to a computer's SASI/SCSI interface. Such controllers were popular
for use with the Atari SASI/SCSI interfaces that require a controller
supporting 256-byte sectors. Suitable ST506 controllers for this purpose
include: Adaptec ACB-4000A (SCSI), Adaptec ACB-4070 (SCSI), Western Digital
WD1002-SHD (SASI), Xebec S1410 (SASI), Xebec S1410A (SASI)