Internal and external 1GB Iomega Jaz drives with media.
The Jaz drive was a removable disk storage system, introduced by the Iomega company in 1995. It has since been discontinued.
The Jaz cartridges were originally released with a 1 GB capacity (there was also 540 MB, but it was unreleased) in a 3½-inch form factor, which was a significant increase over Iomega's most popular product at the time, the Zip drive. The Jaz drive utilized only the SCSI interface (the IDE internal version is rare), but an adapter known as Jaz Traveller was available to connect it to a standard Parallel Port. The capacity was later increased to 2 GB through a drive and disk revision in 1998, before the Jaz line was ultimately discontinued in 2002.
Unlike the Zip, which utilizes floppy disk technology (a PET film disk), the Jaz is based on hard disk drive technology, utilizing rigid platters. The Jaz drive is a type of Removable Rigid Disk (RRD) drive, with two platters (4 writable surfaces) contained within a thick cartridge with sliding door. Like the Zip disk, the Jaz cartridge has a reflective piece in the bottom corner so the drive may detect its capacity before loading (the 1 GB drive will immediately reject 2 GB cartridges.) The drive itself contains the spindle motor, read/write heads, voice-coil actuator and drive controller. The Jaz disk is spun at approximately 5000 RPM. The Jaz drive showed much promise, with a system very similar to high-end laptop hard drives to park the heads and the drive automatically brakes the disk using reverse torque before auto-eject, unlike most of SyQuest's devices. The Jaz drive is much more fragile than the Zip drive and unlike the Zip can only be used lying horizontally on a flat surface.
The Jaz never attained as much success or market penetration as the Zip, and explanations for this vary. Some attribute it to poor marketing on Iomega's part or the fact that 1-2 GB was small compared to modern standards, and its price in terms of cost per megabyte (its price no longer made it competitive with standard hard drives that were slowly increasing in capacity.) Originally the Jaz drive was directed to a higher-end market and saw little in the SOHO or consumer. Compared to the SCSI Zip drive, which used DB25 connectors, the Jaz used the HD50 connectors and supported ID 0-6. The SCSI interface itself was highly priced and was too costly for most home-users. The rising popularity and decreasing price of CD-R/CD-RW and DVD+-R/DVD+-RW drives greatly hurt the success of the drive in terms of relative price per megabyte and that these discs could be read in almost any standard ROM drive (respective of format).
In terms of reliability the Jaz drive by design is much less prone to Click of death. Even so the Jaz drive has its own share of problems, and may still corrupt its own data, causing click of death, as a result of damaged read/write heads writing errors to Jaz cartridges, eventually corrupting them. Although not as common, there are a large number of complaints about the drive's reliability. Earlier Jaz drives were prone to over-heating and in some cases, the loading mechanism jams leaving a cartridge stuck in the drive. Forcibly ejecting the cartridge in this case usually ends in the destruction of both drive and cartridge. Being based on hard disk technology, one big problem that plagues all removable RRD drives is the risk of contaminants ending up in the drive. The Jaz cartridge outside its case is prone to getting dust/grit into it through the hole where the motor drives the platters, or any dust built up on the external case could end up in the drive with the next insertion. Even if this is not the case, the metal sliding door is capable of wearing the plastic, which results in debris. As a result, head-crashes have occurred with some Jaz drives. (see Head crash) Ultimately this may have led to the demise of the system.
Furthermore, the mechanism used to attach the platters to the spindle motor is complex and prone to vibration (as many complained of noisy drives.) Iomega implements an anti-gyro device (much like an optical CD/DVD drive) within the cartridge to prevent this at spin-up, but it loses effectiveness with age. As a result, in bizarre cases the two platters could lose alignment, thus rendering the cartridge unusable.
The modern REV drive seems to be a new attempt to take on the market that the Jaz drive could not, using similar technology. But unlike the Jaz, Iomega decided to place the platter motor within the cartridge and change the door to a flip, very similar to a VHS or DAT cassette in order to reduce number of external moving parts and openings.
Internal platter of an Iomega Jaz 1 GB disk with Magview - Magnetic tracks are clearly visible.
Disassembled Iomega jaz cartridge. Note the reflector-like piece in the upper-left hand corner of the right-most piece.
See also
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