The Hardware Data Compression Unit (HDCU) is a project whose primary purpose is to provide users the capability to transparently increase the storage capacity of their disk storage devices on IBM PC/XTs and compatibles. It must be clarified that this project is not for commercial use but as a basis for further study. It is simply an add-in board which intercepts data during an I/0 (retrieval/store) operation. It performs high-speed and transparent data compression and decompression without any loss of data. Today, most data compressions are done by means of software compression programs due to its very low cost. Moreover, the compression/decompression routines of software products can sometimes be too long and not transparent to the user\u27s environment. Current articles and hand-outs regarding the latest trends in data compression were examined to come up with a transparent compression/decompression system which takes advantage of the speed provided by using a separate microprocessor-based hardware. The thesis group realized the dependency of users on commercial compression softwares for their data compression needs which in most cases, brings about some costs and overheads in time and effort. For this reason, the purpose of the thesis group in developing the system is to take advantage of the benefits brought about by microprocessor-based systems to provide users a faster data compression alternative that compresses files at a reasonable rate (30%-50%) than most commercially available compression software. Therefore, the thesis group feels that the accomplishment of the system will be an enhancement in the way computer users deal with the problem of increasing disk storage
