The Bernoulli Box (or simply Bernoulli, named after Daniel Bernoulli) was a high-capacity (for the time) removable disk storage system that was Iomega's first widely-known product. It was released in 1983.
The drive spun a PET film disk at about 3000 rpm, 1 micrometer over a read-write head, utilizing Bernoulli's principle to pull the flexible disk towards the head as long as the disk was spinning. In theory this made the Bernoulli drive more reliable than a contemporary hard disk drive, since a head crash was impossible.
The original Bernoulli disks came in capacities of 5, 10, and 20 MB. They were roughly 21 cm by 27.5 cm.
The most popular system was the Bernoulli Box II, whose disk cartridges were 13.6 cm wide, 14 cm long and 0.9 cm thick, somewhat resembling a larger version of a 3½-inch floppy disk. Bernoulli Box II disks came in the following capacities: 20 MB, 35 MB, 44 MB, 65 MB, 90 MB (late 1980s), 105 MB, 150 MB, and in 1994, 230 MB. There were five types of drives, grouped by the maximum readable capacity: 20 MB, 44 MB, 90 MB, 150 MB, and 230 MB. The interface was usually SCSI. Drives were available as either internal units, which fit into standard 5¼-inch drive bays, or as external units with one or two drives in a self-contained case connected to the host computer via external SCSI connector. The cartridges had a physical switch similar to that on 3½-inch floppies to enable and disable write protection.
Iomega's later removable storage products such as the Zip and Jaz did not use the Bernoulli technology.
This article was originally based on material from the Free On-line Dictionary of Computing, which is licensed under the GFDL.