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

 

NAME

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

SYNOPSIS

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

DESCRIPTION

      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
           file.
 
      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.
 

NOTES

      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),
      mount_cd9660(8)
 

AUTHORS

      Maxim Sobolev 〈sobomax@FreeBSD.org〉
 

Sections

Based on BSD UNIX
FreeBSD is an advanced operating system for x86 compatible (including Pentium and Athlon), amd64 compatible (including Opteron, Athlon64, and EM64T), UltraSPARC, IA-64, PC-98 and ARM architectures. It is derived from BSD, the version of UNIX developed at the University of California, Berkeley. It is developed and maintained by a large team of individuals. Additional platforms are in various stages of development.