home | help 
MKUZIP(8)		     System Manager's Manual		       MKUZIP(8)

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 al-
     lows 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 us-
	  ing 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 mdcon-
     fig(8), and automatically mount it using mount_cd9660(8) on the mount point
     provided as the first argument to the script.

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

SEE ALSO
     gzip(1),	 zlib(3),    geom(4),	 geom_uzip(4),	  md(4),    mdconfig(8),
     mount_cd9660(8)

AUTHORS
     Maxim Sobolev <sobomax@FreeBSD.org>

FreeBSD 9.1			 March 17, 2006 		       MKUZIP(8)
home | help