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Definition: SSD

(Solid State Drive) An all-electronic, non-volatile storage drive. SSDs are the internal storage in smartphones, tablets and most laptop computers and are increasingly used instead of hard drives in desktop computers. Emerging in the late 1990s, SSDs are faster than hard drives because there is no moving read/write head (zero latency). Without SSDs, smartphones and tablets would never have flourished. As of 2023, there are several dozen manufacturers of SSDs using the SATA or NVMe interface and starting at 128GB. The largest SSD is Seagate's 60TB drive, which uses the SAS interface (see serial attached SCSI). See SATA and NVMe.

SSDs Are Flash Memory
Constructed of NAND flash memory chips, SSD prices have often reached par with hard drives. They are generally more reliable and offer greater protection in hostile environments. In addition, SSDs use less power and are not affected by magnets. See flash memory.

Eventually, there may only be solid state storage, and spinning disk platters will be as obsolete as the punch card. However, hard drive technology is also improving and that may take a while. See disk on module and garbage collection.

More Complex Than Hard Drives
Because flash memory eventually does wear out, SSDs distribute the writes evenly to all the sectors. A great amount of storage management takes place within the drive itself to ensure this uniformity.

Hybrid Drive (SSD and Disk)
SSDs and hard drives can be installed and work together in desktop computers, and as an interim solution for more speed, hybrid drives combine an SSD and hard disk within the same drive (see solid state hybrid drive and Fusion Drive).

Hard Drive Replacement Kits
This kit replaces a computer's hard drive with an SSD. Laptop kits include an external case for the old drive while it is cloned to the SSD. (Image courtesy of Kingston Technology Corporation.)

Less Costly Every Year
In 2014 at Micro Center, a 3TB hard drive (top) was a third the price of a 500GB SSD (middle). By 2020, the same 500GB SSD cost less than $100. In 2023, Best Buy had a sale on 1TB SSDs for $65 (bottom). (Images courtesy of Micro Center and Best Buy.)

Early Fast Storage
In 2001, the MegaRAM (top) used 1GB of RAM for fast storage and sold for $25,000. In case of power failure, batteries saved the RAM's contents to the built-in disk drive. In 2005, the battery in Gigabyte's i-RAM (bottom) kept up to 8GB of RAM current for several hours. See nvSRAM and BBSRAM. (Image courtesy of Imperial Technology, Inc.)

The First SSD - 2MB
In 1977, this Dataram module tied eight magnetic core storage boards together to make the first solid state disk. It held a whopping two megabytes. See core storage. (Image courtesy of Dataram Corporation.)

Early SSDs on PC Cards
Minuscule by today's standards (capacities are in megabytes), these FLASHDISKs added storage to early laptops. Shown here with a CompactFlash card (upper left) for size comparison, they plugged into a PCMCIA slot (see PC Card). (Image courtesy of SanDisk Corporation.)

No, They're Not Dead
Predicted to make hard drives obsolete in the late 1990s, more than two decades later, disks are still thriving, and their capacities are getting larger all the time. This was cut out of a mouse pad from an SSD vendor. See hard disk.