Mail Archives: djgpp/1996/11/09/21:11:46
mert0407 AT sable DOT ox DOT ac DOT uk (George Foot) writes:
>Sorry, I don't really understand tar (yes, I'm a Dos user...), but I
>thought the point of the original article was that tar could achieve
>better compression ratios than zip? The quoted figures certainly looked
>impressive...
Tar does not do compression, it only combines files. The point is that
almost any compressor does better when files are concatenated. (Compressors
look for repeated strings, and giving them more text to work with means
greater chance of finding repeats.) So if you combine files, either with tar
or as an uncompressed ZIP, then compress the single file, you'll get a
smaller distribution file. There are other archivers, such as RAR, which
effectively do this automatically. They call the resulting archive "solid".
The disadvantage of such schemes is that you can't update a single file in
the archive without building the whole thing.
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