updated 02:38 pm EDT, Sat May 24, 2014
New research can boost speed by up to 400 percent, cut power by 60 percent
A team from the Department of Electrical, Electronic and Communication Engineering, Faculty of Science and Engineering of Japan's Chuo University has developed a new technology which will increase the speed, power usage, and product life of not only future Solid State Drives (SSD) but existing ones as well. The technology replaces existing "garbage collection" routines now in use with a new maintenance script, which reduces the effect of fragmentation by writing data on a fragmented page of storage scheduled to be erased and re-allocated next in regular housekeeping.
Data is written to flash memory in units called pages, which are made up of multiple flash memory cells. Allocated memory can only be erased in larger units called blocks, which are made up of multiple pages. If data in some of the pages of the block are no longer needed, only the pages with good data in that block are read and re-written into another previously-erased empty block. The free pages left by not moving the stale data are made available for new data. Existing garbage collection routines are inefficient by comparison, and can add up to 100 milliseconds to write speeds.
The new method alters the database that keeps track of valid addresses for storage. Garbage collection is continued, but more intelligently -- data is placed in a block scheduled to be erased next, which makes for more continuous data stored in one write, as well as fewer copying steps. This cuts down on the number of cell swaps, and slashes the number of writes and re-writes. As a result of the fewer write operations, the drive consumes less power and the life of the drive is extended.
Simulations by Ken Takeuchi and his research team at the university are expecting to see 55 percent fewer write and erase cycles. Devices are also expected to be 60 percent more power efficient in the process over the same period of time. The speed increase of the drive using the new technique varies according to how much space is available, with the new method boosting speed when the drive is near full the most, by up to 400 percent. Since the implementation is in software, the new technology should be able to be retrofitted into older drives with a firmware update as it sees further development.