PrairieTek 220

1988 PrairieTek 220
First 2.5-inch HDD

Why it’s important The new 2.5-inch disk drive form factor, coupled with improvements in reliability and lowering of power, enabled the HDD to participate in the mobile computing market. The PrairieTek 220 provided 20 MB formatted capacity in a 2.5-inch drive which used 30% less space than a 3.5-inch HDD, a perfect fit for laptop computers. With establishment of volume production in 1989, the PrairieTek 220 made it possible for 2.5-inch HDDs to start the displacement of 1" high 3.5-inch HDDs in the growing portable computer market.


PrairieTek was started in 1985 by Terry Johnson, who had pioneered in the transition of the HDD industry to smaller disk drives during the early 1980s first as founder of Miniscribe Corporation and then as founder of Codata, the precursor to Conner Peripherals.

Although PrairieTek's volume production of the 20 MB 2.5-inch drive got underway in 1989, and the company's arrangement for additional production with Alps Electric started in 1990, the market demand was transitioning to higher capacity drives. PrairieTek's single disk 40 MB model, potentially a cost-effective competitive product, wasn't ready in time, and after failing to raise sufficient cash to continue, PrairieTek ceased operations in the summer of 1991. In 1992 Conner and Alps purchased the PrairieTek patent portfolio for $18M in a bankruptcy auction.

By the time PrairieTek went out of business, there were 10 other manufacturers making 2.5" HDDs, all with capacities larger than 20 MB.

Additional information
Oral History of Terry Johnson
"THE EXECUTIVE COMPUTER; The Search for a Lighter Laptop", NY Times, October 2, 1998, credits PrairieTek as first 2.5-inch HDD company
"Conner Peripherals, Alps Electric Gain Edge in Contest for PrairieTek Patents." WSJ, Mar 24, 1992, p. B7

Provenance note: Version 9 of this article was reviewed by the Computer History Museum's Storage SIG on June 20, 2012, and found at that time to require additional work.

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