Is Tape Obsolete?
Tape storage is the granddaddy of storage technology. People who grew up in the 1960s won't forget science fiction movies showing white-coated technicians working in huge data centers in which the walls were lined with tape drives, each one larger than a person.
With tape storage's deep roots in computing, people periodically argue that tape storage has outlived its usefulness. The debate is unsurprising--after all, what other computing technology from the 1960s is still viable today?
The arguments are well known. As the cost of disk storage continues to drop, disk drives will replace tape as the backup medium of choice. After all, restoring data from disks is faster than restoring data from tapes, particularly when you need to retrieve only a limited subset of data. Moreover, the argument goes on, tape drives are complicated and prone to failure. Even if the drive doesn't quit, the media might be bad. And tape jukeboxes have many mechanical parts--and thus many potential points of failure.
But despite arguments that seem compelling on the surface, tape is poised to maintain an important, if somewhat different, role in the storage infrastructure. In the past several weeks, IBM and Quantum have released innovative new technology in the midrange tape-storage arena, which is one of the most rapidly growing segments of the market. Earlier this fall, Quantum also unveiled significant new technology for the high end of the market.
Much of the action in the tape arena is in the midrange market. At the end of October, IBM introduced a new format into the tape storage market that it claims provides the world's highest cartridge capacity to date. Called the IBM TotalStorage Enterprise Tape Drive 3592, the cartridge has an uncompressed capacity of 300GB and a transfer rate of 40MBps. According to IBM, the 3592's capacity exceeds that of Linear Tape-Open (LTO) Generation 2 (LTO-2), a standard developed by a consortium of companies including IBM, and Super DLT (SDLT), Quantum's proprietary format in the midrange market. LTO-2 and SDLT have uncompressed capacities of 200GB. Although both SDLT and Sony's Super Advanced Intelligent Tape (S-AIT), yet another tape format competing in this space, have achieved or will soon achieve 300GB uncompressed capacities, IBM officials argue that because their product roadmap for the 3592 calls for it to rapidly ramp to 1TB capacities, the 3592 will be able to maintain its position as the capacity leader.
The IBM announcement came just weeks after Quantum had unveiled its latest generation of SDLT drives, the SDLT 600. According to Quantum, the SDLT 600, which has a compressed capacity of 600GB, has reestablished SDLT as the price/performance/capacity leader in the midrange market. Furthermore, the SDLT 600 is backward compatible with earlier SDLT drives.
More important, Quantum officials said, is that SDLT had successfully met the challenge posed by LTO-2. According to market research shared by Quantum officials, SDLT grabbed 38 percent of the market in 2002, up from 30 percent in 2001. At LTO-2's release, analysts anticipated that because it was considered to be an open standard supported by industry heavyweights such as IBM and HP, it could shove aside Quantum's proprietary format. That hasn't proven to be the case, according to Quantum officials.
Quantum has also released drives that support the LTO-2 format. And Quantum's new MAKO PX720 enterprise tape library, an important new technology for large-scale data centers, is compatible with LTO technology and all generations of SDLT.
So what do all these goings-on mean for the future of tape? Primarily, they mean that tape should remain an important archiving technology for the foreseeable future. As vendors supply higher capacity and higher throughput tape technology, the cost per gigabyte stored remains compelling. Moreover, a vast amount of information is already stored on tape, and that information must be managed.
Nevertheless, other storage technologies will play an increasingly larger role in the space between primary storage and archiving. Storage infrastructures will become more nuanced, with specific technologies deployed to solve specific problems, such as backup and mirroring in settings in which rapid restore features are important. But as long as tape storage vendors continue to innovate, they should be able to provide attractive solutions for specific storage applications. Tape is far from obsolete, but its role is changing.