Messages in this thread |  | | | Date | Wed, 29 Sep 2004 15:18:46 +0300 | | From | Matti Aarnio <> | | Subject | Re: Compressed filesystems: Better compression? |
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On Tue, Sep 28, 2004 at 11:46:54PM -0400, John Richard Moser wrote: > I wonder what compression Squashfs, cramfs, and zisofs use. I think > cramfs uses zlib compression; I don't know of any other compression in > the kernel tree, so I assume zisofs uses the same, as does squashfs. Am > I mistaken?
Compression algorithms are a bit tough to be used in a random access smallish blocks environments. In long streams where you can use megabytes worth of buffer spaces there is no problem is achieving good performance. But do try to do that in an environment where your maximum block size is, say: 4 kB, and you have to start afresh at every block boundary.
Whatever algorithms you use, there will always be data sequences that are of maximum entropy, and won't compress. Rather they will be presented in streams as is with a few bytes long wrappers around them.
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