IMP 1.12 is a free command-line program for creating and extracting IMP archives, which use variants of the LZ77 and BWT compression algorithms to achieve a high compression ratio. IMP is for advanced users familiar with executing programs from the Windows command prompt. See the documentation included with the program for details on commands. Before using IMP, you must read the license agreement accompanying the program.
IMP is no longer being maintained. It is unable to archive files of size 2Gb or larger.
The string match finder in IMP has been updated and used in Radyx, an open-source mutithreaded LZMA archiver compatible with 7-zip.