Computer terminology is constantly expanding, and the brand-new edition of this dictionary has been updated to keep pace with the latest important innovations in computer science and technology. Emphasis is on helpful information for non-technical home computer users. The book presents more than 3,200 computer-related terms with clear and succinct definitions. Revised features include up-to-date information on Windows Vista, networking, data storage, video, computer security and ethics, and personal computer hardware. Tables, charts, graphs, photos, and line illustrations. Sample Entry: DATA 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. A more 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. See also ZIP FILE; STUFFIT; PCX; JPEG; MPEG.