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Solid State Drives
Have you checked the price of SSDs lately? If pricing has kept you and your customers away from deploying SSDs in mainstream client computing devices, it may be time to have another look. Thanks to a freefall in memory prices that’s been going on essentially since 2007, SSDs have gone from specialty products starting at $1,000 to a sub-$250 commodity now offered as options by many PC makers and white-box providers. An Intel 40-GB SATA SSD sells on the street for as little as $98. On average, SSDs cost as much as $2 per GB compared with around 20 cents per GB for low-end spinning hard drives.
The super-fast boot and access times of Flash-based drives, coupled with their resistance to shock, vibration, electromagnetic erasure and other harsh environmental factors, have made them the drive of choice for builders of ruggedized mobile computers, command and control systems of military and aerospace departments, scientific research systems and for other specialized applications. But pricing remained the primary obstacle to the widespread adoption that normally would allow economies of scale to bring about a price drop (read: LCD panels).
When compared with their spinning counterparts, SSDs all have one thing in common: They deliver orders of magnitude faster performance, particularly with random reads and writes. They’re small, light and use the same interfaces that magnetic hard drives do. Other benefits include instant spinup, zero noise, less power usage and heat dissipation requirements, low latencies and no moving parts to wear out.
But on the subject of wearing out, you should know that SSDs are not all upside. Those made with Flash memory, the less expensive alternative to DRAM, have a limited number of writes over the life of the drive. How limited? That depends on the type of Flash memory being used. Single-level cell (SLC) technology offers the longest life at about 100,000 write cycles per cell, more than enough to outlast a server or laptop. The usable life of multilevel cell (MLC) technology, commonly used in thumb drives, can vary from 1,000 to 10,000 write cycles before it begins to fail, according to memory maker Fujitsu.
Then there’s free block availability, a problem that’s roughly analogous to fragmentation. When data is erased from an SSD, those previously used sectors are normally kicked back to the file system for reallocation. An overabundance of these blank spaces can degrade performance over time.