There was a time not long ago when the title of this post wouldn’t have included SSD. But, with the history of the last couple of years, SSD has earned its right to be included.
A couple of years back I was at a Rocky Mountain Magnetics Seminar (see IEEE magnetics societies) and a disk drive technologist stated that Disks have about another 25 years of technology roadmap ahead of them. During this time they will continue to increase density, throughput and other performance metrics. After 25 years of this they will run up against some theoretical limits which will halt further density progress.
At the same seminar, the presenter said that Tape was lagging Disk technology by about 5-10 years or so. As such, tape should continue to advance for another 5-10 years after disk stops improving at which time tape would also stop increasing density.
Does all this mean the end of tape and disk? I think not. Paper stopped advancing in density theoretically about 2 to 3000 years ago (the papyrus scroll was the ultimate in paper “rotating media”). If we move up to the codex or book form- which in my view is a form factor advance – this took place around 400AD (see history of scroll and codex). Paperback, another form factor advance, took place in the early 20th century (see paperback history).
Turning now to write performance, moveable type was a significant paper (write) performance improvement and started in the mid 15th century. The printing press would go on to improve (paper write) performance for the next six centuries (see printing press history) and continues today.
All this indicates that some data technology, whose density was capped over 2000 years ago, can continue to advance and support valuable activity in today’s world and for the foreseeable future. “Will disk and tape go away” is the wrong question, the right question is “can disk or tape, after SSDs reach price equivalence on a $/GB basis, still be useful to the world”?
I think yes, but that depends on a number of factors as to how the relative SSD-Disk-Tape technologies advance. Assuming someday all these technologies support equivalent Tb/SqIn or spatial density and
- SSD’s retain their relative advantage in random access speed,
- Tape it’s advantage in sequential throughput, volumetric density, and long media life, and
- Disk it’s all around, combined sequential and random access advantage
It seems likely that each can sustain some niche in the data center/home office of tomorrow, although probably not where they are today.
One can see trends being enacted in the enterprise data centers today that are altering the relative positioning of SSDs, disks and tape. Tape is now being relegated to long term, archive storage, Disk is moving to medium-term, secondary storage and SSDs is replacing top tier, primary storage.
More thoughts on this in future posts.
