A solid-state disk or drive (SSD), also called a flash drive, is the next generation hard disk. Though the architecture of an SSD does not employ disks at all, the name is carried over from standard hard disks. In reality an SSD utilizes a special kind of memory chip with erasable, writeable cells that can hold data even when powered off. It might help to think of an SSD as the larger cousin of the memory stick.
Like standard disks, an SSD utilizes a special area for cache memory. Cache memory serves the function of increasing processing speeds by holding data that is needed repeatedly. With the data close at hand in the cache, it does not need to be fetched from the main storage area each time it’s called.
Some SSDs use cache that is volatile, as in synchronous dynamic random access memory (SDRAM), while others use non-volatile cache. The former requires a power source to retain data, just like computer RAM. The latter type retains data even without power.
An SSD has many advantages over a traditional drive. Seek time is decreased significantly, making the SSD very fast. Being sold-state, the drive has no moving parts to malfunction, and does not generate significant heat. It is also lighter than a standard drive, more power efficient, and completely silent. Finally, the SSD is more durable. If dropped or banged it isn’t as likely to be damaged.
There are, however, disadvantages to an SSD over a standard hard drive. For one, standard drives have become so affordable that SSDs cannot compete except in niche markets. Industry insiders expect SSD prices to remain cost-prohibitive until 2009. The SSD also has a life expectancy of erase/write cycles, after which it no longer performs reliably. A hard disk can deliver a good ten years of solid operation. Finally, an SSD has a significantly slower write time than a standard drive.
