Conner Peripherals was founded June 17, 1985 by Seagate Technology co-founder Finis Conner, in San Jose. On Sep. 20, 1995, Conner agreed to merge with Seagate in a deal worth $1 billion. The deal closed February 5, 1996. At the time of the merger, Conner was the second largest hard drive manufacturer, behind Seagate.
History of Conner hard drives

Conner initially concentrated on 3.5-inch drives that stored 40 to 100 megabytes and sold for up to $1,000.
In 1986, Conner merged with CoData, a Colorado start-up founded by Miniscribe cofounders 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 more common 3.5-inch format. The CoData-designed drive became the first Conner Peripherals product. Conner began shipping hard drives in early 1987, initially to Compaq. Compaq and Conner had a symbiotic relationship. During calendar year 1987 Compaq represented about 90% of Conner Peripherals’ sales. Compaq partially financed Conner, and remained a major customer throughout Conner’s existence. Compaq liked to invest in its suppliers or potential suppliers. NexGen was an example of another startup Compaq financed.
Conner’s main innovation was moving more of a drive’s functions to software rather than hardware, decreasing the parts count to reduce price and improve reliability by eliminating potential points of failure.
In April 1988 Conner went public, raising $40 million and earning Finis F. Conner $25 million. In 1990, Conner Peripherals set a record by reaching $1.337 billion in sales in four years, without acquisitions, making it the fastest-growing manufacturing startup in United States history. At its peak, Conner was the second largest maker of hard drives. It was bigger than Western Digital.
How Conner thrived in a competitive late 80s market
The market for hard disks was extremely competitive when Conner started out, with about 70 companies chasing $1.2 billion of business. Many manufacturers only lasted one or two generations of product. Seagate dominated by producing large quantities of standardized disk drives at low margins. Other manufacturers such as Quantum and Maxtor survived by producing small, fast, state-of-the-art drives and selling them at premium prices. Conner took a different approach. Conner sold computer companies on a disk drive before making it. After they agreed on specifications like the drive’s size and power consumption, then Conner designed and built the drives.
By the mid 1990s, the market had consolidated to Seagate, Conner, Maxtor, Quantum, Western Digital, IBM, Fujitsu, and Samsung. Further consolidation was inevitable, and Conner bowed out early, choosing to merge with Seagate and depart the market on its own terms.

David Farquhar is a computer security professional, entrepreneur, and author. He has written professionally about computers since 1991, so he was writing about retro computers when they were still new. He has been working in IT professionally since 1994 and has specialized in vulnerability management since 2013. He holds Security+ and CISSP certifications. Today he blogs five times a week, mostly about retro computers and retro gaming covering the time period from 1975 to 2000.

Do you remember Plus Development hard card? I wanted to buy one for my Tandy 1000sx, as Radio Shack sold hard cards 20mb for $799 which was way too expensive.
the issue I learned is that Plus hard card were like 12″ long and Tandy 1000 lots were 10″ long so it would not physically fit, and Plus never offered a 10″ hard card, though Zuckerboards did.
i ended up buying a 5 1/4 MFM hard drive half drive with MFM controller