Secondary Storage

Performance Enhancement

Three ways to improve the performance of hand disks are:

Disk caching

A portion of RAM used to speed up access to data on a disk. The RAM can be part of the disk drive itself (sometimes called a hard disk (cache or buffer) or it can be general-purpose RAM in the computer that is reserved for use by the disk drive (sometimes called a soft disk cache). Hard disk caches are more effective, but they are also much more expensive, and therefore smaller. Nearly all modern disk drives include a small amount of internal cache.

Redundant arrays of inexpensive disks (RAID)

technology that allowed computer users to achieve high levels of storage reliability from low-cost and less reliable PC-class disk-drive components, via the technique of arranging the devices into arrays for redundancy.

File compression and decompression
The file compression and decompression take an existing file or files and produce a file or files that are compressed versions of the originals. The compression is also lossless, but the compression is not transparent to applications. An application can only operate on such files with the assistance of a file compression library. In addition, the only operations you can perform on such files are creating a compressed file from an original and recovering the original data from the decompressed version. Editing is typically not supported, and seeking is limited if supported at all.