From: agulbra@flipper.pvv.unit.no (Arnt Gulbrandsen) Subject: Re: Why ZIP/UNZIP slower than DOS version? Date: 7 Aug 1992 01:46:15 GMT
In article <1992Jul31.050921.19572@athena.mit.edu> chchen@stat.fsu.edu writes:
>I am using the zip/unzip binaries from tsx-11(or banjo?). The zipping
>/unzipping speed is far slower than the pkzip/pkunzip DOS version,
>especially for large files (>= 100k). Anyone has the same problem?
Others have blamed C, but my guess is that this is only a small part
of the difference. The big part, IMHO, is that pkzip looks at the
first 1500 (or is it 3000?) bytes of the file and chooses one of two
or three precomputed Shannon-Fano trees depending on what kind of file
it looks like, while zip builds a tree for each particular file.
Better compression, less speed.
--Arnt