Emerging Database course DATA COMPRESSION THEORY AND TECHNIQUES

Emerging Database course: DATA COMPRESSION: THEORY AND TECHNIQUES INTRODUCTION

DATA COMPRESSION: THEORY AND TECHNIQUES INTRODUCTION Despite continuing improvements in storage and transmission technology the rapidly growing amount of information stored on and transmitting between computers has increased the need for text compression. A huge amount of information can be stored on a single CD but sometimes this is not enough to avoid multivolume applications. It is known that a simple ad hoc method can compress an English text to around 70% of its original size, and the best techniques have a compression ratio about 25%. In case of Braille the used compression processes can reduce the size of books by 20%. For computers, compression can increase the amount of information stored on a disk. If archive-and compressed-data are stored on magnetic tapes not only fewer tapes are needed, but fewer shelves are used to store them and less time is taken to read them. The compression of transmitted data has another benefits: the cost of transmission is reduced and the effective speed of transmission also increases.

REFERENCES • Timon C. Du. , Emerging Database System Architectures • Bochmann, G. Concepts for Distributed Systems Design • Capron, H. L. Computers: Tools for an Information Age