HAP (or Hap, or Hap and Pah) is compression software for DOS, developed by Harald Feldmann and Hamarsoft.
There are probably just two publicly-distributable versions of HAP: v2.10 and v3.00. There are other versions that are commercial software. The file format is proprietary.
HAP 2.10 compresses a single file. HAP 3.00+ makes multi-file compressed archives.
The HAP software consists of a "HAP" program for compression, and a "PAH" program for decompression.
V3.00 files start with the byte
0x91, followed by ASCII "
V2.10 files seem to start with bytes
91 4a 2e.
Note that the 3.x releases below all contain the same software. Only the documentation is updated.
- v2.10 (1992-03-11)
- Hap & Pah 3.00 (1992-11-15)
- HAP300.ZIP - Same as previous
- HAP300RE.ZIP (1994-01-07?)
- hap305bp.com (1996-03-21)
- Hamarsoft products → HAP 3.05bp (actually 3.06, 1997-07-30)
- hap306.zip - Same as previous
- hap40td2.zip (1996-06-18?) - Non-functional HAP 4.02 demo, also includes HAP 3.00.