technology that reduces the size of a computer file. Especially important for files used on Web pages: graphics and sound files are compressed so they can be downloaded faster. Compression methods are described as lossless (no data is lost) or lossy (some data is sacrificed to achieve greater compression).
the storage of data in a way that makes it occupy less space than if it were stored in its original form. For example, long sequences of repeated characters can be replaced with short codes that mean "The following character is repeated 35 times," or the like.Amore thorough form of data compression involves using codes of different lengths for different character sequences so that the most common sequences take up less space.
Most text files can be compressed to about half their normal size. Digitized images can often be compressed to 10 percent of their original size (or even more if some loss of fine detail can be tolerated), but machine-language programs sometimes cannot be compressed at all because they contain no recurrent patterns.
in a computer system, storage of data in a format that occupies less space than the original form. In order to effect data compression, special software packages are required to compress the data and to reopen it to its original size. Because data can be compressed to a fraction of its original size, data compression is particularly useful in communications, allowing for faster transmission of information.
