Conner Peripherals

Conner Peripherals (commonly referred to as Conner) was a company that manufactured hard drives for personal computers. Conner Peripherals was founded in 1985 by Seagate Technology co-founder and San Jose State University alumnus Finis Conner () (1943– ) but it in itself never produced a product. In 1986, they merged with CoData, a Colorado start-up founded by MiniScribe founders Terry Johnson and John Squires. CoData was developing a new type of small hard disk that put the capacity of a 5.25-inch drive into the smaller (and now commonplace) 3.5-inch format. The CoData drive was the first Conner Peripherals product. The company was partially financed by Compaq, who was also a major customer for many years.

Conner's drives were notable for eschewing the "tub" type of head-disk assembly, where the disks are inside a large base casting shaped like a square bowl or vault with a flat lid; instead, they preferred the flat base plate approach, which was more resistant to shock and less likely to warp or deform when heated. Their first drives had the base plate carrying the disks, head arm and actuator enclosed inside a long aluminum cartridge, fixed to a bulkhead on the other side with two screws and sealed with a large, square O-ring. Conner's 1/3-height (1-inch thick) drives used a domed, cast aluminum lid with four screws, one on each corner, sealed to the base plate with a rubber gasket. The printed circuit board was bolted to the bottom of the base plate, with the mounting holes for the drive drilled into tabs cast into the sides of the base plate. This design would be Conner's trademark look well into the 1990s.

Logically, Conner's drives had some of the characteristics of the original MiniScribe drives (of which John Squires had also been a designer), with a large amount of intelligence built into the drive's central processing unit (CPU); Conner drives used a single Motorola 68HC11 microcontroller, and ran a proprietary real-time operating system that implemented the track-following algorithms (the "servo" system) in software, as well as managing the bus interface. Running these functions in software saved a lot of hardware; in 1986, most drives used a separate PID controller for the spindle, and used a CPU mainly to manage the bus interface and generate positioning pulses for a stepper motor. SCSI support added yet another CPU to interpret the SCSI commands, and track-following servos required analog components that often populated entire circuit boards of their own, thus driving up costs.

...
Wikipedia