Diablo Data Systems

Diablo Data Systems was a division of Xerox created by the acquisition of Diablo Systems Inc. in 1972.

The company was best known for the HyType I, HyType II, and Diablo 630 daisywheel printers, but also produced the hard disk drives that were resold by DEC as the RK02 and RK03. Lead engineers Jonny Skolnick and Eli Fenyes headed operations at the division.

...
Wikipedia