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Despite the ability of removable disk cartridges to match or exceed tape in terms of durability and ease of use, for most companies it will still come down to the price delta between tape and disk cartridges. Disk is approximately the same price as tape, or just slightly more, depending on how much data there is to back up. Pricing for internal tape drives (cartridge and tape) like Travan and LTO start at $360 and $1,000, respectively, while pricing for a disk drive for Imation Odyssey Removable Hard Disk Storage System, Iomega Corp. REV and RDX disk cartridges ranges between $250 and $600. Assuming the data to be backed up is small (fewer than 100GB), and only one disk cartridge is needed daily for a complete backup, disk and tape work out to roughly the same price.
One key feature disk cartridges offer over tape cartridges is their longer life and five-year warranties. But despite their lower per-cartridge price, tape cartridges wear out faster than disk cartridges. When counting the upfront cost of tape cartridges plus the cost of replacement due to wear over a three- to five-year period, disk cartridges may be the less-costly alternative.
Another factor is the backward and forward compatibility of most removable disk drives and cartridges. Most new tape drives can only read and write to tape cartridges that match the current tape generation, and only read older tape formats going back a couple of generations. Conversely, most
Normally there's lag time between when higher capacity disk drives are released and when they're available in disk cartridges. When a new, higher capacity disk drive is released, it usually carries a premium price and is available only in a vendor's proprietary disk cartridge casing. To circumvent this, Idealstor provides a casing into which off-the-shelf SATA disk drives can be installed before they're inserted into their backup appliance. This allows users to immediately purchase and implement new, higher capacity SATA disk drives at existing retail prices.
ProStor Systems also recognizes the inherent delays associated with releasing higher capacity disk cartridges. Rather than manufacturing its own RDX disk drives, it stole a page from the LTO playbook and licensed the RDX technology to companies like Imation and Tandberg Data. ProStor anticipates that competition between manufacturers over time will result in faster time to market for new, higher capacity disk cartridges as well as lower prices.
Removable disk drives are emerging as a viable alternative to tape. Though acceptance at the enterprise level remains at least a few years away, most removable disk drives are suitable for small businesses.
This was first published in March 2007