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Standard Performance Evaluation Corporation

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SPEC CPU2000 Benchmark Description File

Benchmark Name


Benchmark Author

Julian Seward <>

Benchmark Program General Category


Benchmark Description

256.bzip2 is based on Julian Seward's bzip2 version 0.1. The only difference between bzip2 0.1 and 256.bzip2 is that SPEC's version of bzip2 performs no file I/O other than reading the input. All compression and decompression happens entirely in memory. This is to help isolate the work done to only the CPU and memory subsystem.

Input Description

256.bzip2's reference workload has three components: a large TIFF image, a program binary, and a source tar file. These components were selected as a reasonably representative set of things that bzip2 might most often be used on.

Each input set is compressed and decompressed at two different blocking factors ("compression levels"), with the end result of the process being compared to the original data after each decompression step.

Output Description

The output files provide a brief outline of what the benchmark is doing as it runs. Output sizes for each compression and decompression are printed to facilitate validation, and the results of decompression are compared with the input data to ensure that they match.

Programming Language


Known portability issues



Last updated: 5 October 1999