The ST-506 and ST-412 (sometimes written ST506 and ST412[1]) were early hard disk drive products introduced by Seagate in 1980 and 1981 respectively,[1] that later became construed as hard disk drive interfaces: the ST-506 disk interface and the ST-412 disk interface. Introduced in 1980, the ST-506 was the first 5.25 inch HDD. Its successor, the ST-412, was introduced in 1981 and implemented a refinement to the seek speed, and increased the drive capacity from 5 MB to 10 MB, but was otherwise highly similar.[1]
Beginning with its selection as the hard drive subsystem for the original IBM XT[1] disk drive controllers supporting the ST-412 interface grew to become ubiquitous in the personal computer industry,[2] The ST-412 interface and its variants were the de facto industry standard for personal computer hard disks until the advent and wider adoption of the IDE or ATA interface in the early 1990s.
Both interfaces used MFM encoding; the subsequent extension of the ST-412 interface, the ST-412HP interface, used RLL encoding for a 50% increase in capacity and bit rate.
- ^ a b c d "Beginnings: MFM drives of the 1980s". redhill.com. Red Hill Technology. n.d. Retrieved 16 September 2020.
Note: 'ST-412' is correct. You will often see 'ST412' written in error.
- ^ "Changes to the ST-506/ST-412 Interface". Retrieved 2019-05-27.