hard drive history

beginings: mfm drives of the 1980s

Seagate ST-412 also incorrectly known as the 'Seagate ST412'

Photo: Red Hill.

Seagate ST-412

You'll go a long way to find a drive that's older than this one: the ST-412 powered many of the first hard disk-equipped micro computers, notably the original IBM PC-XT.

In 1979 industry veteran Al Shugart, already well-known as the former CEO of floppy drive pioneer Shugart Associates, got together with Finis Conner to co-found a new company, Shugart Technology, which was soon to become Seagate. This was the beginning of storage as we know it. Shugart was responsible for the genesis of the two hard drive interfaces that were to dominate the PC world for decades, SCSI and ST-506/412. In 1980 Shugart produced the world's first 5.25 inch hard drive: the 5MB ST-506. The 10MB ST-412 followed in 1981, and with its selection by IBM for the PC-XT, Seagate was on the way to becoming the world's largest drive manufacturer.

The longevity of some of these old drives is astonishing. We don't know the manufacturing date of the one illustrated above, but in January 2002 we pulled an identical one out of a working machine — that's close to 20 years of service from a device with a design life of no more than five years.

Notice the yellow-labelled black stepper motor at bottom left, and the dull orange of the oxide-coated platters.

If you've grown up using a 286 or a 486 you might have become familiar with BIOS drive types. Back before hard drive auto-detection, the parameters for any particular model of drive had to be hard-coded in the system BIOS. Most 20MB drives were Type 2 or Type 6, nearly all 40MB IDE drives were Type 17, and all more recent drives are user-defined as Type 46 or 47. It is no accident that the ST-412 was Type 1.

Note: "ST-412" is correct. You will often see "ST412" written in error.

Data rate5 Mbit/secSpin rate3600 RPM
Seek time85msActuatorStepper
Platter capacity5MBInterfaceMFM
AT drive type1Form5¼" full-height
ST-41210MB4 heads1981