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



      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 so that the geom_uzip(4)
      class will be able to decompress the resulting image at run-time.  This
      allows for a significant reduction of size of disk image at the expense
      of some CPU time required to decompress the data each time it is read.
      The mkuzip utility works in two phases:
      1.   An infile image is split into clusters; each cluster is compressed
           using zlib(3).
      2.   The resulting set of compressed clusters along with headers that
           allow locating each individual cluster is written to the output
      The options are:
      -o outfile
              Name of the output file outfile.  The default is to use the input
              name with the suffix .uzip.
      -s cluster_size
              Split the image into clusters of cluster_size bytes, 16384 bytes
              by default.  The cluster_size should be a multiple of 512 bytes.
      -v      Display verbose messages.


      The 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 gzip(1).  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 a few bytes from that cluster have to be read.
      The mkuzip utility inserts a short shell script at the beginning of the
      generated image, which makes it possible to “run” the image just like any
      other shell script.  The script tries to load the geom_uzip(4) class if
      it is not loaded, configure the image as an md(4) disk device using
      mdconfig(8), and automatically mount it using mount_cd9660(8) on the
      mount point provided as the first argument to the script.
      The mkuzip utility exits 0 on success, and >0 if an error occurs.
      gzip(1), zlib(3), geom(4), geom_uzip(4), md(4), mdconfig(8),


      Maxim Sobolev 〈〉


Based on BSD UNIX
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