| Phillip Lougher | a650bcc | 2014-08-08 22:02:51 +0100 | [diff] [blame] | 1 | SQUASHFS 4.2 - A squashed read-only filesystem for Linux |
| 2 | |
| 3 | Copyright 2002-2011 Phillip Lougher <phillip@lougher.demon.co.uk> |
| 4 | |
| 5 | Released under the GPL licence (version 2 or later). |
| 6 | |
| 7 | Welcome to Squashfs 4.2. This is a tools only release, support for Squashfs |
| 8 | filesystems is in mainline (2.6.29 and later). |
| 9 | |
| 10 | New features in Squashfs-tools 4.2 |
| 11 | ---------------------------------- |
| 12 | |
| 13 | 1. Support for XZ compression |
| 14 | 2. Support for compressor specific options |
| 15 | |
| 16 | Compatiblity |
| 17 | ------------ |
| 18 | |
| 19 | Mksquashfs 4.2 generates 4.0 filesystems. These filesystems are fully |
| 20 | compatible/interchangable with filesystems generated by Mksquashfs 4.0 and are |
| 21 | mountable on 2.6.29 and later kernels. |
| 22 | |
| 23 | XZ compression |
| 24 | -------------- |
| 25 | |
| 26 | Squashfs now supports XZ compression. |
| 27 | |
| 28 | XZ support is in 2.6.38 and newer kernels. |
| 29 | |
| 30 | New Mksquashfs options |
| 31 | ---------------------- |
| 32 | |
| 33 | -X<compressor-option> |
| 34 | |
| 35 | Compression algorithms can now support compression specific options. These |
| 36 | options are prefixed by -X, and are passed to the compressor for handling. |
| 37 | |
| 38 | The compression specific options supported by each compressor can be |
| 39 | found by typing mksquashfs without any arguments. They are displayed at the |
| 40 | end of the help message, e.g. |
| 41 | |
| 42 | Compressors available and compressor specific options: |
| 43 | gzip (no options) (default) |
| 44 | lzo (no options) |
| 45 | xz |
| 46 | -Xbcj filter1,filter2,...,filterN |
| 47 | Compress using filter1,filter2,...,filterN in turn |
| 48 | (in addition to no filter), and choose the best compression. |
| 49 | Available filters: x86, arm, armthumb, powerpc, sparc, ia64 |
| 50 | -Xdict-size <dict-size> |
| 51 | Use <dict-size> as the XZ dictionary size. The dictionary size |
| 52 | can be specified as a percentage of the block size, or as an |
| 53 | absolute value. The dictionary size must be less than or equal |
| 54 | to the block size and 8192 bytes or larger. It must also be |
| 55 | storable in the xz header as either 2^n or as 2^n+2^(n+1). |
| 56 | Example dict-sizes are 75%, 50%, 37.5%, 25%, or 32K, 16K, 8K |
| 57 | etc. |