Enhancing Compression Ratio of Variable-Byte Scheme for Inverted File Index

Abstract

One of the most important characteristics of file compression is to preserve memory with all its temporary and permanent images, in addition to maintaining the speed of performance in the process of compression and decompression and increase the frequency range in the transmission and reception from long distances. The examined the performance of Variable-Byte compression scheme over sequences of integers. Variable-Byte algorithm which has high compression speed and decompression speed while the algorithm's compression ratio is weak in the case of small integers. Has been designed enhanced compression algorithm (Variable-5bits) based on Variable-Byte algorithm, evaluated the performance of Variable-5bits thorough experiments on synthetic data sets with random integers in the range 0 – 2^31 ,the ratio of compression is improved from 4 to 6.4 in the case of small integers. In the case of large integers, the variable-5bits algorithm is roughly equal in the compression ratio with the Variable-Byte algorithm. A number of experiments were performed to test the compression ratio in the variable-5bits in different and varied samples when the range is small between integers, the compression ratio is high and when the range is large between the integers we get a low compression ratio.