Removable Cartridge Disk

Removable cartridge disks filled the gap between a floppy and a sealed hard drive from 1982 to the early 2000s. Two companies, Iomega and SyQuest, fought over it, and they made opposite engineering bets. Iomega kept flexible media and let air hold it near the head. SyQuest put a rigid disk in a cartridge.

Iomega's Bernoulli Box appeared in 1982. StorageNewsletter, republishing the Museum of Obsolete Media, says it spun an 8-inch PET disk at 1,500 rpm inside an 11 by 8-inch rigid cartridge, using Bernoulli's law to pull the disk toward the head while a cushion of air kept them apart, and that a power cut or a knock moved the disk away from the head rather than toward it. Iomega's 1994 annual report describes the later 5.25-inch version: a patented head contour creates a vacuum between head and media that gives stable, intimate contact at the gap, and Iomega says that is what permitted very high linear densities (vendor claim). The same filing lists drives of 20, 44, 90, 150 and 230 MB, with the 150 MB MultiDisk shipping from October 1992 and the 230 MB model from September 1994.

SyQuest was founded on 27 January 1982 by Syed Iftikar, a Seagate co-founder, with four colleagues. Its 1983 fact sheet gives 8 August 1982 as the first shipment, of the 3.9-inch SQ306 with 6.38 MB unformatted (5 MB formatted). The CHM Storage SIG history, written by Iftikar himself, says the Q-100 cartridge held a 3.9-inch aluminium disk with a plated recording layer under sputtered carbon, that the team chose IBM's 3.9-inch floppy size expecting it to become the standard, and that Sony's 3.5-inch size won instead. It also describes the cartridge-change problem and the answer: the disk itself acted as a pump impeller that moved and filtered the contaminated air that entered during a cartridge change, aiming for the removable drive to behave like a fixed one 10 seconds after spin-up.

Neither design was trouble-free. The SIG history says that after the first 10,000 SQ306 drives shipped, soft ferrite heads were found eroding against the hard carbon disks, and the drives were recalled and fitted with ceramic heads. SyQuest's own 1983 fact sheet had said the overcoating eliminated head crashes (vendor claim). The same history says the 5.25-inch family became the media interchange standard for desktop publishing, with 90% of that market in 1991; that figure is the author's and is not independently confirmed here.

Iomega's answer to a mass market was the Zip. Design News reported that it was unveiled at Comdex in November 1994, about seven months after its conception, with a linear actuator positioning the head to within 0.5 micron, a 2,941 rpm spin, and heads similar to a hard disk's. Iomega's 1994 annual report says Zip uses 'high capacity flexible media and removability technologies developed in the Company's original Bernoulli products', with Winchester-style nanoslide heads having a special air-bearing surface, and that it began shipping 100 MB drives in March 1995. The Museum's catalogue entry says Zip's non-contact head flew above the surface like a hard disk's.

Jaz went the other way. Iomega's 1999 annual report says the Jaz 1GB began shipping in December 1995 with tri-pad thin-film heads, dynamic head loading and a dual rigid-platter cartridge whose capture system stops the platters rattling when out of the drive, and that a 2GB model shipped from February 1998. The same report warns that, because Jaz uses hard-drive components, contaminants, heavy duty cycles or heat and humidity may shorten life. This card found no independent source for the popular claim that Jaz drives crashed heads often; the 6% return figure is the only reliability number in the sources opened.

The end came from both flanks. In April 1999 Iomega bought SyQuest's intellectual property, inventory and fixed assets and the two firms dropped their patent suits, according to Iomega's 1999 filing. Zip faced the 'Click of Death' complaint: a class action filed 10 September 1998 alleged that a defect made Zip drives click and damage drives or disks. Iomega continued to dispute the allegations when it proposed a settlement in April 2001, and the plaintiffs' lawyer said it could affect as many as 28 million buyers.