In his Storage Decisions presentation on solid-state storage, Dennis Martin, president of the analyst firm Demartek, discusses the unique characteristics of solid-state, as well as the differences between single, triple and multi-layer flash.
"Obviously, we're taking some kind of memory technology and presenting it as a storage device. That's the basic underlying premise here," said Martin.
While the technology is pricier than the equivalent capacity in a hard drive, he says pricing is improving. "The good news is that prices are dropping and capacities are getting larger. Still more expensive on a per-gigabyte basis than a hard drive, but trends are looking good."
He also addressed the performance benefits and tradeoffs of the different versions of flash: while single-layer cell (SLC) technology offers the fastest performance and the longest-possible endurance, it also has the highest cost of the flash technologies out there. Meanwhile, multi-layer cell and triple-layer cell flash are less expensive, but don't equal the performance of SLC, according to Martin.
The technology is also different from hard drives due to the separate performance characteristics of reads and writes of data to SSDs. "Writing is harder than reading. Reading is very quick and easy. Writes take more effort, so there's an asymmetric relationship between reads and writes with SSDs that you don't find on hard drives. Hard drive reads and writes take about the same amount of time," he said.
Despite some of the tradeoffs of various flash formats and differences from hard drives, solid-state offers practical benefits as well. "You've got all kinds of other benefits -- low power, low weight, very quiet -- very nice from the environmental standpoint," said Martin.