1.\" ---------------------------------------------------------------------------- 2.\" "THE BEER-WARE LICENSE" (Revision 42): 3.\" <sobomax@FreeBSD.org> wrote this file. As long as you retain this notice you 4.\" can do whatever you want with this stuff. If we meet some day, and you think 5.\" this stuff is worth it, you can buy me a beer in return. Maxim Sobolev 6.\" ---------------------------------------------------------------------------- 7.\" 8.\" $FreeBSD$ 9.\" 10.Dd March 17, 2006 11.Dt MKUZIP 8 12.Os 13.Sh NAME 14.Nm mkuzip 15.Nd compress disk image for use with 16.Xr geom_uzip 4 17class 18.Sh SYNOPSIS 19.Nm 20.Op Fl v 21.Op Fl o Ar outfile 22.Op Fl s Ar cluster_size 23.Ar infile 24.Sh DESCRIPTION 25The 26.Nm 27utility compresses a disk image file so that the 28.Xr geom_uzip 4 29class will be able to decompress the resulting image at run-time. 30This allows for a significant reduction of size of disk image at 31the expense of some CPU time required to decompress the data each 32time it is read. 33The 34.Nm 35utility 36works in two phases: 37.Bl -enum 38.It 39An 40.Ar infile 41image is split into clusters; each cluster is compressed using 42.Xr zlib 3 . 43.It 44The resulting set of compressed clusters along with headers that allow 45locating each individual cluster is written to the output file. 46.El 47.Pp 48The options are: 49.Bl -tag -width indent 50.It Fl o Ar outfile 51Name of the output file 52.Ar outfile . 53The default is to use the input name with the suffix 54.Pa .uzip . 55.It Fl s Ar cluster_size 56Split the image into clusters of 57.Ar cluster_size 58bytes, 16384 bytes by default. 59The 60.Ar cluster_size 61should be a multiple of 512 bytes. 62.It Fl v 63Display verbose messages. 64.El 65.Sh NOTES 66The compression ratio largely depends on the cluster size used. 67.\" The following two sentences are unclear: how can gzip(1) be 68.\" used in a comparable fashion, and wouldn't a gzip-compressed 69.\" image suffer from larger cluster sizes as well? 70For large cluster sizes (16K and higher), typical compression ratios 71are only 1-2% less than those achieved with 72.Xr gzip 1 . 73However, it should be kept in mind that larger cluster 74sizes lead to higher overhead in the 75.Xr geom_uzip 4 76class, as the class has to decompress the whole cluster even if 77only a few bytes from that cluster have to be read. 78.Pp 79The 80.Nm 81utility 82inserts a short shell script at the beginning of the generated image, 83which makes it possible to 84.Dq run 85the image just like any other shell script. 86The script tries to load the 87.Xr geom_uzip 4 88class if it is not loaded, configure the image as an 89.Xr md 4 90disk device using 91.Xr mdconfig 8 , 92and automatically mount it using 93.Xr mount_cd9660 8 94on the mount point provided as the first argument to the script. 95.Sh EXIT STATUS 96.Ex -std 97.Sh SEE ALSO 98.Xr gzip 1 , 99.Xr zlib 3 , 100.Xr geom 4 , 101.Xr geom_uzip 4 , 102.Xr md 4 , 103.Xr mdconfig 8 , 104.Xr mount_cd9660 8 105.Sh AUTHORS 106.An Maxim Sobolev Aq sobomax@FreeBSD.org 107