DOS/Windows - May 12, 2002 Edition
Macintosh - Oct. 7, 2002 Edition
JPEG - August 9, 2007 Edition
The Archive Comparison Test is a set of benchmarks designed to show the state of the art in lossless data compression. It contains benchmarks on various types of data for compression speed, uncompression speed, and compression ratio. The DOS/Windows version of ACT was first published in September 1992. The Macintosh version was first published in December 1999.
For more information about data compression, check out Compression Links Info and the Data Compression Library.