Solid State Drives

Several companies, dating back to the late 1970's, designed various solid state drives. Storage Tek, Santa Clara Systems, Sharp, Amiga, and Apple were a few of the first. M-Systems designed the first flash-based device which we know as SanDisk now.
Solid state drives are seen by the system as just another drive. These drives are most useful in portable devices since there are no mechanical parts. They operate solely on semiconductor circuitry so there's no real danger in bumping the device. They mostly are produced using nonvolatile flash memory but some are produced with DRAM volatile memory.
As a cost reduction measure, flash memory devices have gone from NOR flash to single-level cell (SLC) NAND flash and multi-level cell (MLC) NAND flash. Each chip is capable of being manufactured with more storage and uses about the same size footprint as older chips.
Solid state drives are faster and have lower access time since they have no moving parts, they use less power, make no noise, are reliable up to between 300,000 and 500,000 write operations, and take up considerably less room than a standard hard disk drive. There are down sides to solid state drives though. The price is still high, the storage space is low (but climbing), power disruptions and ESD are more hazardous, they will not necessarily last longer than a hard disk drive, and they have slower write speeds.
That being said, the future of hard disk drives is slowly being reduced except for large computer systems and servers. The development of longer lasting and larger capacity solid state devices are being pursued by many manufacturers and the cost is dropping accordingly.