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Hard Disk Compliment

The next step up in capacity, 500MB to 1GB, is enough to back-up a reasonably large disk partition. Most such devices also offer good enough performance to function as secondary, if slow, hard disks. Magnetic and MO technology again predominates, but in this category they come up against competition from a number of Phase-change devices.

Above 1GB, the most commonly used removable drive technology is derived from that found in conventional hard disks, which not only allows high capacities but also provides fast performance, pretty close to that of conventional fixed hard disks. These drives behave just like small, fast hard disks.

Magnetic storage and MO are again the dominant technologies. Generally the former offers better performance and the latter larger storage capacity. However, MO disks are two-sided and only half the capacity is available on-line at any given time.

Right from its launch in mid-1996 the Iomega Jaz drive was perceived to be a ground-breaking product. The idea of having 1GB removable hard disks with excellent performance was one that many high-power PC users had been dreaming of for a long time. When the Jaz appeared on the market there was little or no competition to what it could do; it allowed users to construct audio and video presentations and transport them between machines. Not only that, such presentations could be executed directly from the Jaz media, with no need to transfer the data to a fixed disk.

The Jaz is essentially little different from a hard disk, except that the twin platters sit in a cartridge protected by a dust-proof shutter which springs open on insertion to provide access to well-tried Winchester read/write heads. The drive is affordably priced, offers a fast 12ms seek time coupled with a data transfer rate of 5.4 MBps and comes with a choice of IDE or SCSI-2 interfaces. It’s a good choice for audio-visual work, capable of holding an entire MPEG movie.

SyQuest’s much-delayed riposte to the Jaz, the 1.5GB SyJet, finally came to market in the summer of 1997. It was faster than the Jaz, offering a data transfer rate of 6.9 MBps and came in parallel-port and SCSI external versions as well as an IDE internal version. However, despite its larger capacity and improved performance the SyJet failed to achieve the same level of success as the Jaz.

When first launched in the Spring of 1998, the aggressively priced 1GB SparQ appeared to have more prospect of turning the tables on Iomega. Available both in external parallel port or internal IDE models, the SparQ achieved significantly improved performance as a consequence of using high density single platter disks and a spindle speed of 5,400rpm. It turned out it to too little too late though, and on 2 November 1998 SyQuest was forced to suspend trading and subsequently file for bankruptcy under Chapter 11 U.S. law. A few months later, in early 1999, the company was bought-out by arch-rival Iomega.

However, it wasn’t long before Iomega’s apparently unchallengeable position in the removable storage arena came under threat from another quarter. Castlewood Systems had been founded in 1996 – interestingly by one of the founders of SyQuest – and in 1999 its removable media hard drives began to make the sort of waves that had been made by the ground-breaking Iomega Zip drive some years previously.

The Castlewood ORB is the first universal storage system to be built using cutting-edge magnetoresistive (MR) head technology, making them very different from other removable media drives that use 20-year-old hard drive technology based on thin film inductive heads. MR hard drive technology – first developed by IBM – permits a much larger concentration of data on the storage medium and is expected to allow areal densities to grow at a compound annual rate of 60% in the next decade.

The Castle ORB drive uses 3.5in removable media that is virtually identical to that used in a fixed hard drive. With a capacity of 2.2GB and a claimed maximum sustained data transfer rate of 12.2 MBps, it represents a significant step forward in removable drive performance, making it capable of recording streaming video and audio. One of the benefits conferred by MR technology is a reduced component count, and this is behind two of the ORB’s other advantages over its competition – cooler operation and an estimated MTBF rating 50 percent better than other removable cartridge products. Both will be important factors as ORB drives are adapted to mobile computers and a broader range of consumer products – such as digital VCRs – which either use batteries as a power source or have limited space for cooling fans.

And if all this wasn’t enough – in mid-1999 the ORB drive and media were available at a costs that were around a factor of 2 and 3 respectively less than competitive products.

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