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+.\" ----------------------------------------------------------------------------
+.\" "THE BEER-WARE LICENSE" (Revision 42):
+.\" <sobomax@FreeBSD.ORG> wrote this file. As long as you retain this notice you
+.\" can do whatever you want with this stuff. If we meet some day, and you think
+.\" this stuff is worth it, you can buy me a beer in return.       Maxim Sobolev
+.\" ----------------------------------------------------------------------------
+.\"
+.\" $FreeBSD$
+.\"
+.Dd July 29, 2001
+.Dt MDGZIP 8
+.Os
+.Sh NAME
+.Nm mkuzip
+.Nd compress a
+.Xr geom_uzip 4
+image
+.Sh SYNOPSIS
+.Nm
+.Op Fl v
+.Op Fl o Ar outfile
+.Op Fl s Ar cluster_size
+.Ar infile
+.Sh DESCRIPTION
+The
+.Nm
+utility compresses a disk image file in such a way that the
+.Xr geom_uzip 4
+class will be able to decompress resulting image in run-time
+when it loaded into memory. This allows for significant reduction
+of memory footprint of memory-based filesystem 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:
+.Bl -enum
+.It
+An
+.Ar infile
+image is split into clusters and each cluster compressed using
+.Xr zlib 3 .
+.It
+Resulting set of clusters along with headers allowing to
+independently locate each individual cluster is written into
+output file.
+.El
+.Pp
+The options are:
+.Bl -tag -width Fl
+.It Fl o Ar outfile
+Name the output file
+.Ar outfile .
+The default is to use the input name with the suffix
+.Sq .uzip .
+.It Fl s Ar cluster_size
+Use
+.Ar cluster_size
+as the size of chunks the file being split up into.  Default value
+is 16K.  The
+.Ar cluster_size
+should be multiple of block size of the
+.Xr geom_uzip 4
+device (usually 512 bytes).
+.It Fl v
+Display verbose messages.
+.El
+.Sh NOTES
+Compression ratio largely depends on the cluster size used. For
+large cluster sizes of (16K and higher) typical compression ratios
+are only 1-2% less than those achieved with the
+.Xr gzip 1
+utlity.  However, it should be kept in mind that larger cluster
+sizes lead to higher overhead in the
+.Xr geom_uzip 4
+class, as the class has to decompress the whole cluster even if
+literally only several bytes from that cluster have to be read.
+.Sh SEE ALSO
+.Xr gzip 1 ,
+.Xr zlib 3 ,
+.Xr geom_uzip 4 ,
+.Xr boot 8 ,
+.Xr loader 8
+.Sh DIAGNOSTICS
+Exit status is 0 on success and >0 on error.
+.Sh AUTHORS
+.An Maxim Sobolev Aq sobomax@FreeBSD.org .