Second Storage

Disk caching :

A temporary storage area where frequently accessed data can be stored for rapid access. Once the data is stored in the cache, it can be used in the future by accessing the cached copy rather than re-fetching or recomputing the original data.

Redundant arrays of inexpensive disks (RAID) :

Organization of multiple disks into a large, high performance logical disk.

Disk arrays stripe data across multiple disks and access them in parallel to achieve:-
(i) Higher data transfer rates on large data accesses

(ii) Higher I/O rates on small data accesses.

Data striping also results in uniform load balancing across all of the disks, eliminating hot spots that otherwise saturate a small number of disks, while the majority of disks sit in is original.

File compression and decompression :

Image compression is minimizing the size in bytes of a graphics file without degrading the quality of the image to an unaccceptable level. The reduction infile size allows more images to be stored in a given amount of disk or memoryspace