A more contentious idea is the use of solid-state memory as a substitute for disk. With no moving parts, solid state is much faster and much more reliable than disk storage, but it remains significantly more expensive than disk.
"Everything I've read and understood about solid state memories, they will never have the recording capacities at a sensible cost for the amount of information people are talking about," says Mark Heers, marketing manager at storage vendor EMC. "I think it will always be a niche solution."
Moore's Law can be relied upon to reduce the cost of memory over time, but at the same time, the amount of data people need to store is accelerating at approximately the same rate. This means solid state storage will always remain as expensive -- compared with the amount of it needed -- as it is today. "It's going to scale down in dollars per gigabyte, but people will always be storing more and more," explains Heers.
On the other hand, Dilip Kandlur, head of IBM's storage systems research division, sees one niche application of solid state being quite popular: as an intermediary between disk systems and main memory. "As processing speeds increase, we are coming to a point where the access times to memory are increasing relative to the processor cycles in the CPU. This is a phenomenon called the memory wall, that memory appears to be further and further away. While you have very large main memories in computing systems, you would probably benefit from having non-volatile solid-state memory placing an additional level in the hierarchy, to be able to give you better access and performance," Kandlur says. The lack of moving parts allows truly random access to data, which could provide significant performance advantages for transactional systems, he adds.
So long, tape?
For about as long as pundits have been predicting that holographic storage is just around the corner, they have also been predicting the demise of tape in the day-to-day running of a datacentre. Greg Bowden, national business manager at systems integrator Dimension Data, says there is definitely a convergence between disk and tape that may eventually lead to less emphasis on tape use. "There's a lot of solutions out there that look almost identical to the ones 10 years ago. Software's changed, the tape drives have increased performance and capacity, but the premise of it hasn't," he says. But new technologies coming into play now will "reinvigorate how customers protect their data, from snapshot technology to the mixing of tape and disk to bringing archiving solutions into place," he explains.
On the other hand, Nieboer believes tape faces a much smaller challenge than disk in coping with burgeoning storage requirements. "In disk I've got a relatively small surface area that I've got to put an increasing number of bits on. In tape I have a piece of half-inch media that's hundreds or thousands of feet long," he says. By 2005, Nieboer predicts tapes will have half a terabyte of uncompressed capacity, meaning at least a terabyte of storage per tape with compression. "A couple of years later you'll get a terabyte uncompressed that goes to two terabytes with compression. Tape has a long life ahead of it," he assures us.
Nieboer is more sceptical about the future of optical storage in the datacentre, despite technologies such as Blu-Ray and ultra dense optical increasing the storage capacity of optical storage. "Optical disk is really not participating in the datacentre anymore. The old optical [WORM disks and the like] is dead as a doornail in the datacentre, and the new optical [CDs and DVDs] isn't there yet in terms of datacentre readiness," he explains. "To me it's more a distribution model of data rather than a storage device."
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Sony already have a 500GB native capacity tape, the Super-AIT. But where is quantum storage...?