Terry Johnson

Terry Johnson (1935–2010) was an American engineer and entrepreneur notable for his work on hard disk drives (HDD) and for pioneering the transition of computers to using smaller disk drives.

After college in 1963, Johnson worked in engineering and management roles at IBM for seven years, followed by two years at Memorex. He then joined Disk Systems Corporation, which was acquired by Storage Technology Corporation (StorageTek or STC). At StorageTek, he helped develop the Super Disk, a hard disk drive (HDD) that had a storage capacity of 800 megabytes (MB), the highest available at the time.

In 1980, Johnson left StorageTek to establish a startup called Miniscribe, a manufacturer of 5.25-inch HDDs. After leaving Miniscribe in 1984, he co-founded a new company, CoData, that merged with Conner Peripherals the following year. CoData's 3.5-inch drive became the company's first product. Additionally, in 1985, Johnson co-founded PrairieTek, the first to manufacture smaller 2.5-inch drives.

Johnson died in the Northwest Territories, Canada, when his private aircraft crashed during his return from a canoe trip.

Early years and education Terry Johnson was born in Ogden, Utah, on March 14, 1935, to Clifford Johnson Sr. and Myrtle Johnson. He grew up in Ogden but spent his summers on a ranch in Clover Valley, Nevada. After graduating from high school in 1953, he started college but left in 1954 to enlist in the US Navy for four years. During his time in the Navy, Johnson worked as an electronics technician and often felt like a second-class citizen. In 1958, following his military service, he was, therefore, highly motivated to finish his college education to avoid feeling that way for the rest of his life. Johnson earned a Bachelor's degree in electrical engineering from the University of Utah in 1961. After graduating, he received job offers from computer companies Control Data and IBM; however, he chose to pursue a Master's degree first. He worked as an engineer at Hercules Power Company, an aerospace company, for one year before being accepted into graduate studies at the University of California, Berkeley (UC Berkeley). Johnson went on to earn his Master's degree from UC Berkeley in 1963. His final project at the company involved designing circuitry for the IBM 3330 during its early development stage.

After leaving IBM in 1970, Johnson joined Memorex in Silicon Valley, CA. While working on the servo electronics system, he helped develop the 8800 Super Disk, a high-end rotary actuator hard disk drive (HDD). It was named the "Super Disk" due to its large storage capacity of 800 MB, far exceeding any other drive available at the time. This project led to several inventions.

During his five years at StorageTek, Johnson worked as the Program Manager for the 8650 drive, a double density equivalent to the IBM 3350, and then advanced to Director of Engineering for the Disk Division. In 1980, Johnson left the company by mutual agreement after being transitioned to a staff position.

CoData (Conner Peripherals) Three months after Johnson resigned from Miniscribe, John Squires also left the company. The pair decided to form a new company called CoData, aiming to produce a 3.5-inch disk drive. Although other companies, including Miniscribe, had developed a 3.5-inch disk drive, it was not yet a practical product. Squire's design of the CP340 set a new standard for integrated control over disk drive dynamics by microcode.

PrairieTek After leaving CoData, Terry Johnson persuaded Disk Systems cohort Jim Morehouse to join him in founding PrairieTek in 1986 to build a 2.5" drive, a new form factor aimed at the emerging laptop market. Computer companies were pursuing smaller size, lower weight, and longer battery life. Established disk companies recognized the need for something smaller than the 3.5" disk drive and Johnson saw a niche for this new kind of disk drive. Scaling down a 3.5" design was not sufficient for the laptop market where shock-resistance and low power consumption were important. The technical team at PrairieTek designed a drive that became a prototype for successive generations of disk drives. Ramp Load/Unload was a key feature of PrairieTek drives.

But being early to market with a good new design was not enough. According to "The Innovator's Dilemma":

Demand for 2.5" drives rose but PrairieTek filed for bankruptcy in 1991. Johnson did not blame his competitors for the company's demise, but saw it as a failure to execute on his part. At the time of his death, he was a resident of Longmont, Colorado.