Corvus Systems was a computer technology company that offered, at various points in its history, computer hardware, software, and complete PC systems.
History
Corvus was founded by Michael D'Addio and Mark Hahn in 1979. This San Jose, Silicon Valley company pioneered in the early days of personal computers, producing the first hard disk drives, data backup, and networking devices, commonly for the Apple II series. The combination of disk storage, backup, and networking was very popular in primary and secondary education. A classroom would have a single drive and backup with a full classroom of Apple II computers networked together. Students would log in each time they use the computer and access their work via the Corvus Omninet network, which also supported eMail.
They went public in 1981 and were traded on the NASDAQ exchange. In 1985 Corvus acquired a company named Onyx & IMI. IMI (International Memories Incorporated) manufactured the hard disks used by Corvus.
The New York Times followed their financial fortunes. They were a modest success in the stock market during their first few years as a public company. The company's founders left Corvus in 1985 as the remaining board of directors made the decision to enter the PC clone market. D'Addio and Hahn went on to found Videonics in 1986, the same year Corvus discontinued hardware manufacturing.
In 1987, Corvus filed for Chapter 11. That same year two top executives left. Its demise was partially caused by Ethernet establishing itself over Omninet as the local area network standard for PCs, and partially by the decision to become a PC clone company in a crowded and unprofitable market space.
Disk drives and backup
The company modified the Apple II's DOS operating system to enable using Corvuss 10 MB Winchester technology hard disk drives. Apple DOS normally was limited to the usage of 140 KB floppy disks. The Corvus disks not only increased the size of available storage but were also considerably faster than floppy disks. These disk drives were initially sold to software engineers inside Apple Computer.
The disk drives were manufactured by IMI (International Memories Incorporated) in Cupertino, California. Corvus provided the hardware and software to interface them to Apple II's, Tandy TRS-80s, Atari 800, and S-100 bus systems. Later, the DEC Rainbow, Corvus Concept, IBM PCs and Macs were added to the list. These 5 MB and 10 MB drives were twice the size of a shoebox and initially retailed for US$5000. Corvus sold many stand alone drives whose numbers increased as they became shared over Omninet. This allowed sharing a then-very costly hard drive among multiple inexpensive Apple II computers. An entire office or classroom could thus share a single Omninet-connected Corvus drive.
Certain models of the drives offered a tape backup option called "Mirror" to make hard disk backups using a VCR, which was itself a relatively new technology. A standalone version of "Mirror" was also made available. Data was backed up at roughly one megabyte per minute which resulted in five or ten-minute backup times. Tapes could hold up to 73MB. Even though Corvus had a on this technology, several other computer companies later used this technique.
A later version of tape backup for the Corvus Omninet was called The Bank. and was a standalone Omninet connected device that used custom backup tape media that were very similar in shape and size to today's DLT tapes. Both the Corvus File Server and The Bank tape backup units were in white plastic housings roughly the size of two stacked reams of paper.
Networking
In 1980 Corvus came out with the first commercially successful local area network (LAN), called Omninet''. Most Ethernet deployments of the time ran at 3 Mbit/s and cost one or two thousand dollars per computer. Ethernet also used a thick and heavy cable that felt like a lead pipe when bent, which was run in proximity to each computer, often in the ceiling plenum. The weight of the cable was such that injury to workers from ceiling failure and falling cables was a real danger. A transceiver unit was spliced or tapped into the cable for each computer, with an additional AUI cable running from the transceiver to the computer itself.
Corvus's Omninet ran at one megabit per second, used twisted pair cables and had a simple add-in card for each computer. The card cost $400 and could be installed by the end user. Cards and operating software were produced for both the Apple II and the IBM PC and XT. At the time, many networking experts said that twisted pair could never work because "the bits would leak off", but it eventually became the de facto standard for wired LANs.