What is a Solid State Drive (SSD)?

A solid-state drive (SSD), also called a flash drive, is type of hard drive. Though the architecture of an SSD is quite different from traditional hard drives, the name is carried over. 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 drives, 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. Most SSDs have a slower write time than standard drives, although this can vary, depending on the type of flash memory used and number of chips. Standard drives are also relatively less expensive than SSDs, although the price has fallen. The SSD also has a limited life expectancy of erase/write cycles, after which it no longer performs reliably. A hard disk may be able to deliver a good ten years of solid operation.

Many people in the field believe that flash drives or SSDs will eventually replace traditional hard drive technology. By the time this happens, the disadvantages will likely have been eliminated or significantly mitigated. Even today, an SSD can extend the life of a notebook battery, decrease the weight of the machine, make it quieter, and increase read performance.

Capacity is also a major factor in the adoption of solid state drives. The average notebook computer equipped with a SSD will have around 128 to 512GB of storage. This is roughly equivalent to what laptops of several years ago came equipped with. Today, most laptops feature 500GB or more of storage with a hard drive. Desktop systems have an even greater disparity between SSD and hard drives as the average desktop comes with 1TB or more of storage.

Even with the huge difference in capacity, many people are finding that most computers have far more storage capacity than they typically have. Only a large collection of raw digital photo files and high definition video files will likely fill up hard drives quickly. As a result, solid state drives will generally offer a sufficient level of storage for most laptop computers.


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