Editor's Note:
Fred Moore wrote this and sent it over today as background to the EMC announcement incorporating flash disks into the DMX-4.
STK introduced the first solid state disk (SSD), the 4305, in 1978 at $8,800/MB - that's $8.8M/GB with an initial capacity of 45MB and then 90MB a year later with an access time of .6ms. Memorex, Intel and Hitachi also had SSDs. IBM's announcement of Expanded Storage all but killed SSD in 1985. This was the reason that IBM always said it would never do an SSD. Imperial and a few others kept the industry alive with small SSDs for Unix & Windows but they could never make it over a $20M/year business and spent nothing on marketing.
The Flash SSDs are one of the new and exciting products in the industry now. Prices for consumer flash SSDs are $25-$200/GB compared to $600-$800/GB for DRAM SSDs. Consumer flash devices have a slower read time of 0.2 ms versus a DRAM SSD at .02 ms today and the substantially slow writes of consumer flash take 4-5ms compared to .02 ms writes on DRAM SSDs. However the STEC Zeus IOPS SSDs that EMC is supporting reportedly handle reads in about .25 ms, comparable to consumer flash but perform writes ten times faster in about 0.4 ms (at the device level).
Nonetheless, a common misconception occurs when measuring disk and SSD devices as if both are a capacity device. Disks should be measured on $/GB(capacity) and SSDs should be measured on $/IOPs (performance).
Action Item: EMC's announcement incorporating flash drive technology represents the possible resurgence of SSD in high end disk systems and will likely have ripple effects throughout the industry. Users should understand the benefits of the technology and apply it where appropriate. Comparisons with conventional disks are simple but not meaningful as value for performance (not value for capacity) is the key to understanding the benefits of SSD.
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