Solid state drives are a new type of storage devices for computers. They have been available several years but are gaining in popularity. Solid state drives (SSD) are drives that may either be inside the computer or external drives that are used to store data.
Traditionally we used hard drives on computers to do most of storage (although in early 1980s the method was floppy disks). With the hard drive information was recorded magnetically on hard surfaces that revolved thousands of times per minute and read access head moved back and forth to the correct track with the data. The movable disk and read-write arms were potential breakdowns from hardware failure and limited how fast the data could be retrieved waiting to turn to correct location and arm move to track.
With the SSD the is recorded in large flash memory so there are no moving parts and works similar to the thumb USB flash drives. Information can be written much quicker and read quicker. The price of SSD is coming down and the SSD drives are getting larger and larger capabilities to store data like hard drives. Within the next few years I expect SSD to be cheaper and bigger than hard drives.
A major problem to both type drives is they both work magnetically so they can be erased with magnets or with magnetic forces. They information is fully read-writable in both cases so malware can damage the data.
The physical size of SSD drives is like hard drives.