A disk drive that uses memory chips instead of rotating platters for data storage. Used in battery-powered handheld devices as well as laptop computers, solid state disks (SSDs) are faster than regular disks because there is zero latency (no read/write head to move). They are also more rugged than hard disks and offer greater protection in hostile environments.

Increasingly, solid state technologies are available as a storage option in regular laptops, not just ruggedized ones. It will take some time, but eventually, spinning disk platters will be as obsolete as the punch card (see future memory chips).

Non-Volatile and Volatile
Most solid state disks use non-volatile flash memory; however, some use volatile DRAM or SRAM chips that are backed up by a built-in disk drive or UPS in case of power failure. Also called an "electronic disk," a solid state disk emulates the sector format of a disk drive and is generally a plug-for-plug replacement for it. As memory has gotten less expensive, the storage capacity of solid state devices has increased tremendously. See disk on module, flash disk, dynamic RAM and static RAM.