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MKUZIP(8)               FreeBSD System Manager's Manual              MKUZIP(8)

     mkuzip - compress disk image for use with geom_uzip(4) class

     mkuzip [-v] [-o outfile] [-s cluster_size] infile

     The mkuzip utility compresses a disk image file in such a way that the
     geom_uzip(4) class will be able to decompress resulting image in run-
     time.  This allows for significant reduction of size of disk image at the
     expense of some CPU time required to decompress the data each time it is
     read.  Internally, operation is done in two phases as follows:

     1.   An infile image is split into clusters and each cluster compressed
          using zlib(3).

     2.   Resulting set of compressed clusters along with headers allowing to
          independently locate each individual cluster is written into output

     The options are:

     -o outfile
             Name the output file outfile.  The default is to use the input
             name with the suffix .uzip.

     -s cluster_size
             Use cluster_size as the size of chunks the file being split up
             into.  Default value is 16384 bytes.  The cluster_size should be
             a multiple of 512 bytes.

     -v      Display verbose messages.

     Compression ratio largely depends on the cluster size used.  For large
     cluster sizes (16K and higher), typical compression ratios are only 1-2%
     less than those achieved with the gzip(1) utlity.  However, it should be
     kept in mind that larger cluster sizes lead to higher overhead in the
     geom_uzip(4) class, as the class has to decompress the whole cluster even
     if only several bytes from that cluster have to be read.

     The mkuzip inserts tiny shell script at the beginning of the generated
     image, which makes it possible to ``run'' the image just like any other
     shell script.  This script tries to load geom_uzip(4) class if it is not
     loaded, configure image as an md(4) disk device using mdconfig(8)
     utility, and automatically mount it using mount_cd9660(8) utility to the
     mount point provided as a first argument.

     gzip(1), zlib(3), geom(4), geom_uzip(4), md(4), mdconfig(8),

     The mkuzip utility exits 0 on success, and >0 if an error occurs.

     Maxim Sobolev <>

FreeBSD 11.0-PRERELEASE       September 10, 2004       FreeBSD 11.0-PRERELEASE


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