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.

Format details
There is a 16-bit field at offset 8 that specifies the compression or encoding method.

Identification
Files begin with bytes.

Specifications

 * libmspack: COMPRESS.EXE file formats

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)

See also MS-DOS installation compression.

Sample files
Compression method 2:

Compression method 3:
 * MS-DOS 6.2 → *.IMA → *.??_
 * MS-DOS 6.2 → *.IMA → *.??_
 * MS-DOS 6.2 → *.IMA → *.??_
 * MS-DOS 6.2 → *.IMA → *.??_

Compression method 4:
 * Microsoft Works 3.0 → MMWORKS300.iso → MSWORKS/*.??_