I've just been reading

http://www.pkware.com/documents/casestudies/APPNOTE.TXT

which contains the specification of the file format used by PKZIP. 
(Otherwise known as a "zip file".)

Jesus, this file format is so old and crufty! >_< Talk about lame...

Anyway, on line 554 we find the following:

       compression method: (2 bytes)

           (see accompanying documentation for algorithm
           descriptions)

           0 - The file is stored (no compression)
           1 - The file is Shrunk
           2 - The file is Reduced with compression factor 1
           3 - The file is Reduced with compression factor 2
           4 - The file is Reduced with compression factor 3
           5 - The file is Reduced with compression factor 4
           6 - The file is Imploded
           7 - Reserved for Tokenizing compression algorithm
           8 - The file is Deflated
           9 - Enhanced Deflating using Deflate64(tm)
          10 - PKWARE Data Compression Library Imploding (old IBM TERSE)
          11 - Reserved by PKWARE
          12 - File is compressed using BZIP2 algorithm
          13 - Reserved by PKWARE
          14 - LZMA (EFS)
          15 - Reserved by PKWARE
          16 - Reserved by PKWARE
          17 - Reserved by PKWARE
          18 - File is compressed using IBM TERSE (new)
          19 - IBM LZ77 z Architecture (PFS)
          97 - WavPack compressed data
          98 - PPMd version I, Rev 1

It's not actually 100% clear whether these codes are decimal or 
hexdecimal. But either way, I have a Zip file with nothing seems to be 
able to read, and all the files are compressed with method 0x0063. 
(That's 99 decimal.)

So I guess that's why nothing can read this Zip file then...

Man, spending a day staring at hex dumps is no fun at all! >_<

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