Microsoft KWAJ installation compression
Microsoft KWAJ installation compression refers to a compressed file format used for software installation by Microsoft and their installer tools. "KWAJ" refers to the signature bytes at the beginning of a compressed file.
KWAJ is a relative of some similar formats, most importantly the one known as "SZDD". For the other formats, see MS-DOS installation compression and Microsoft SZ installation compression.
KWAJ is more sophisticated than SZDD, though the relationship between them is not clear.
Contents |
Format details
There is a 16-bit field at offset 8 that specifies the compression or encoding method.
| Compression code | Description |
|---|---|
| 0 | Uncompressed (rare) |
| 1 | XOR (rare) |
| 2 | Okumura's LZSS |
| 3 | LZ77 + Huffman |
| 4 | MSZIP (based on DEFLATE) |
Identification
Files begin with bytes 4b 57 41 4a 88 f0 27 d1.
Specifications
Software
- MSDN Library - April 1996 → MSDN15_1.iso → MSDNSMPL/PROD/EISPAK11/DECOMP.EXE - Decompression utility for DOS; supports compression methods 2, 3, 4
- libmspack → msexpand (decompress only)
- Deark
See also MS-DOS installation compression#Software.
Sample files
Compression method 2:
- MOUSE901.ZIP → *.??$
Compression method 3:
- POWERTCP.ZIP
- PRTFRM41.ZIP
- NSWP20.ZIP
- MS-DOS 6.2 → *.IMA → *.??_
Compression method 4:
- Microsoft Works 3.0 → MMWORKS300.iso → MSWORKS/*.??_
