MSZIP
From Just Solve the File Format Problem
MSZIP (Microsoft ZIP) is a compression scheme used in some Microsoft formats. It is an extension of DEFLATE. It is simpler than zlib, but similar in concept.
It is one of the compression options in CAB format, and in MS-DOS installation compression.
Format details
The uncompressed data is divided into blocks of at most 32KB. Each block is compressed using DEFLATE. Two signature bytes, ASCII "CK", are prepended to each block. Exactly how the compressed blocks are stored in the file depends on the file format.
The blocks are not compressed completely independently. The 32KB DEFLATE history buffer is maintained between blocks, though the Huffman trees are discarded.