- WIMLIB
+ INTRODUCTION
+
+This is wimlib version 1.8.3-BETA (September 2015). wimlib is a C library for
+creating, modifying, extracting, and mounting files in the Windows Imaging
+Format (WIM files). wimlib and its command-line frontend 'wimlib-imagex'
+provide a free and cross-platform alternative to Microsoft's WIMGAPI, ImageX,
+and DISM.
+
+ INSTALLATION
+
+To install wimlib and wimlib-imagex on UNIX-like systems, you can compile from
+source (e.g. './configure && make && sudo make install'). Alternatively, check
+if a package has already been prepared for your operating system. Example files
+for Debian and RPM packaging are in the debian/ and rpm/ directories.
+
+To install wimlib and wimlib-imagex on Windows, just download and extract the
+ZIP file containing the latest binaries. See README.WINDOWS for more details.
+
+All official wimlib releases are available from http://wimlib.net.
+
+ WIM FILES
+
+A Windows Imaging (WIM) file is an archive designed primarily for archiving
+Windows filesystems. However, it can be used on other platforms as well, with
+some limitations. Like some other archive formats such as ZIP, files in WIM
+archives may be compressed. WIM archives support multiple compression formats,
+including LZX, XPRESS, and LZMS. All these formats are supported by wimlib.
+
+A WIM archive contains one or more "images", each of which is a logically
+independent directory tree. Each image has a 1-based index and usually a name.
-This is wimlib version 1.2.4 (February 2013). wimlib can be used to read,
-write, and mount files in the Windows Imaging Format (WIM files). These files
-are normally created by using the `imagex.exe' utility on Windows, but this
-library provides a free implementation of imagex for UNIX-based systems.
-
- WIM FILES
-
-A Windows Imaging (WIM) file is an archive. Like some other archive formats
-such as ZIP, files in WIM archives may be compressed. WIM archives support two
-Microsoft-specific compression formats: LZX and XPRESS. Both are based on LZ77
-and Huffman encoding, and both are supported by wimlib.
-
-Unlike ZIP files, WIM files can contain multiple independent toplevel directory
-trees known as images. While each image has its own metadata describing a
-directory tree and file access modes, files are not duplicated for each image;
-instead, each file is included only once in the entire WIM. Microsoft did this
-so that in one WIM file, they could do things like have 5 different versions of
-Windows that are almost exactly the same.
-
-Microsoft provides documentation for the WIM file format, XPRESS compression
-format, and LZX compression format. The XPRESS documentation is acceptable, but
-the LZX documentation is not entirely correct, and the WIM documentation itself
-is incomplete.
-
-A WIM file may be either stand-alone or split into multiple parts.
-
- PROGRAMS
-
-wimlib provides a public API for other programs to use, but also comes with two
-programs: `imagex' and `mkwinpeimg'.
-
-`imagex' is intended to be like the imagex.exe program from Windows. `imagex'
-can be used to create, extract, and mount WIM files. Both read-only and
-read-write mounts are supported. See the man page `doc/imagex.1' for more
-details.
-
-`mkwinpeimg' is shell script that makes it easy to create a customized bootable
-image of Windows PE that can be put on a CD or USB drive, or published on a
-server for PXE booting. See the main page `doc/mkwinpeimg.1' for more details.
-
-There is an additional program, `wimapply', that is not installed by default.
-It can be used to build a small executable with the ability to apply a WIM image
-from a standalone WIM, without having to build the whole shared library. This
-could be useful on Linux boot clients that only need to be able to apply a WIM,
-not capture/split/join/append/export/mount a WIM. See `programs/wimapply.c'.
-
- COMPRESSION RATIO
-
-wimlib can create XPRESS or LZX compressed WIM archives. Currently, the XPRESS
-compression ratio is slightly better than that provided by Microsoft's software,
-while the LZX compression ratio is approaching that of Microsoft's software but
-is not quite there yet. Running time is as good as or better than Microsoft's
-software, especially with multithreaded compression, available in wimlib v1.1.0
-and later.
-
-The following tables compare the compression ratio and performance for creating
-a compressed Windows PE image (disk usage of about 524 MB, uncompressed WIM size
-361 MB):
-
- Table 1. WIM size
-
- XPRESS Compression LZX Compression
- wimlib imagex (v1.2.1): 138,971,353 bytes 131,379,943 bytes
- Microsoft imagex.exe: 140,406,981 bytes 127,249,176 bytes
-
- Table 2. Time to create WIM
-
- XPRESS Compression LZX Compression
- wimlib imagex (v1.2.1, 2 threads): 11 sec 17 sec
- Microsoft imagex.exe: 25 sec 89 sec
-
- NTFS SUPPORT
-
-As of version 1.0.0, wimlib supports capturing and applying images directly to
-NTFS volumes. This was made possible with the help of libntfs-3g from the
-NTFS-3g project. This feature supports capturing and restoring NTFS-specific
-data such as security descriptors, alternate data streams, and reparse point
-data.
-
-The code for NTFS image capture and image application is complete enough that it
-is possible to apply an image from the "install.wim" contained in recent Windows
-installation media (Vista, Windows 7, or Windows 8) directly to a NTFS volume,
-and then boot Windows from it after preparing the Boot Configuration Data. In
+WIM archives provide data deduplication at the level of full file contents. In
+other words, each unique "file contents" is only stored once in the archive,
+regardless of how many files have that contents across all images.
+
+A WIM archive may be either stand-alone or split into multiple parts.
+
+An update of the WIM format --- first added by Microsoft for Windows 8 ---
+supports solid-mode compression. This refers to files being compressed together
+(e.g. as in a .tar.xz or .7z archive) rather than separately (e.g. as in a .zip
+archive). This usually produces a much better compression ratio. Solid
+archives are sometimes called "ESD files" by Microsoft and may have the ".esd"
+file extension rather than ".wim". They are supported in wimlib since v1.6.0.
+
+ IMAGEX IMPLEMENTATION
+
+wimlib itself is a C library, and it provides a documented public API (See:
+http://wimlib.net/apidoc) for other programs to use. However, it is also
+distributed with a command-line program called "wimlib-imagex" that uses this
+library to implement an imaging tool similar to Microsoft's ImageX.
+wimlib-imagex supports almost all the capabilities of Microsoft's ImageX as well
+as additional capabilities. wimlib-imagex works on both UNIX-like systems and
+Windows, although some features differ between the platforms.
+
+Run `wimlib-imagex' with no arguments to see an overview of the available
+commands and their syntax. For additional documentation:
+
+ * If you have installed wimlib-imagex on a UNIX-like system, you will find
+ further documentation in the man pages; run `man wimlib-imagex' to get
+ started.
+
+ * If you have downloaded the Windows binary distribution, you will find the
+ documentation for wimlib-imagex in PDF format in the "doc" directory,
+ ready for viewing with any PDF viewer. Please note that although the PDF
+ files are converted from UNIX-style "man pages", they do document
+ Windows-specific behavior when appropriate.
+
+ COMPRESSION RATIO
+
+wimlib (and wimlib-imagex) can create XPRESS, LZX, or LZMS compressed WIM files.
+wimlib's compression codecs usually outperform and outcompress their Microsoft
+equivalents. Although results will vary depending on the data being compressed,
+the table below shows results for a common use case: creating an x86 Windows PE
+image ("boot.wim"). Each row shows the compression type, the size of the
+resulting WIM file in bytes, and the time it took to create the file. When
+possible, the results with the Microsoft equivalent are included.
+
+ =============================================================================
+ | Compression || wimlib (v1.8.3) | WIMGAPI (Windows 10) |
+ =============================================================================
+ | None [1] || 361,314,224 in 2.7s | 361,315,338 in 3.0s |
+ | XPRESS [2] || 137,954,729 in 3.0s | 140,457,081 in 6.4s |
+ | XPRESS (slow) [3] || 135,147,054 in 8.0s | N/A |
+ | LZX (quick) [4] || 130,098,933 in 3.3s | N/A |
+ | LZX (normal) [5] || 126,310,241 in 9.9s | 127,293,110 in 18.5s |
+ | LZX (slow) [6] || 125,884,919 in 17.4s | N/A |
+ | LZMS (non-solid) [7] || 116,150,698 in 23.4s | N/A |
+ | LZMS (solid) [8] || 88,108,326 in 55.6s | 88,771,800 in 90.9s |
+ | "WIMBoot" [9] || 166,892,801 in 3.0s | 169,108,689 in 8.9s |
+ | "WIMBoot" (slow) [10] || 165,004,333 in 7.8s | N/A |
+ =============================================================================
+
+Notes:
+ [1] '--compress=none' for wimlib-imagex; '/compress:none' for DISM.
+
+ [2] '--compress=XPRESS' for wimlib-imagex; '/compress:fast' for DISM.
+ Compression chunk size defaults to 32768 bytes in both cases.
+
+ [3] '--compress=XPRESS:80' for wimlib-imagex; no known equivalent for DISM.
+ Compression chunk size defaults to 32768 bytes.
+
+ [4] '--compress=LZX:20' for wimlib-imagex; no known equivalent for DISM.
+ Compression chunk size defaults to 32768 bytes.
+
+ [5] '--compress=LZX' or '--compress=LZX:50' or no option for wimlib-imagex;
+ '/compress:maximum' for DISM.
+ Compression chunk size defaults to 32768 bytes in both cases.
+
+ [6] '--compress=LZX:100' for wimlib-imagex; no known equivalent for DISM.
+ Compression chunk size defaults to 32768 bytes.
+
+ [7] '--compress=LZMS' for wimlib-imagex; no known equivalent for DISM.
+ Compression chunk size defaults to 131072 bytes.
+
+ [8] '--solid' for wimlib-imagex. Should be '/compress:recovery' for DISM,
+ but only works for /Export-Image, not /Capture-Image. Compression chunk
+ size in solid resources defaults to 67108864 bytes in both cases.
+
+ [9] '--wimboot' for wimlib-imagex; '/wimboot' for DISM.
+ This is really XPRESS compression with 4096 byte chunks, so the same as
+ '--compress=XPRESS --chunk-size=4096'.
+
+ [10] '--wimboot --compress=XPRESS:80' for wimlib-imagex;
+ no known equivalent for DISM.
+ Same format as [9], but trying harder to get a good compression ratio.
+
+Note: wimlib-imagex's --compress option also accepts the "fast", "maximum", and
+"recovery" aliases for XPRESS, LZX, and LZMS, respectively.
+
+Testing environment:
+
+ - 64 bit binaries
+ - Windows 10 virtual machine running on Linux with VT-x
+ - 4 CPUs and 4 GiB memory given to virtual machine
+ - SSD-backed virtual disk
+ - All tests done with page cache warmed
+
+The compression ratio provided by wimlib is also competitive with commonly used
+archive formats. Below are file sizes that result when the Canterbury corpus is
+compressed with wimlib (v1.8.3), WIMGAPI (Windows 8.1), and some other
+formats/programs:
+
+ =====================================================
+ | Format | Size (bytes) |
+ =====================================================
+ | tar | 2,826,240 |
+ | WIM (WIMGAPI, None) | 2,814,254 |
+ | WIM (wimlib, None) | 2,814,216 |
+ | WIM (WIMGAPI, XPRESS) | 825,536 |
+ | WIM (wimlib, XPRESS) | 787,356 |
+ | tar.gz (gzip, default) | 738,796 |
+ | ZIP (Info-ZIP, default) | 735,334 |
+ | tar.gz (gzip, -9) | 733,971 |
+ | ZIP (Info-ZIP, -9) | 732,297 |
+ | WIM (wimlib, LZX quick) | 686,420 |
+ | WIM (WIMGAPI, LZX) | 651,866 |
+ | WIM (wimlib, LZX normal) | 623,718 |
+ | WIM (wimlib, LZX slow) | 619,382 |
+ | WIM (wimlib, LZMS non-solid) | 581,046 |
+ | tar.bz2 (bzip, default) | 565,008 |
+ | tar.bz2 (bzip, -9) | 565,008 |
+ | WIM (WIMGAPI, LZMS solid) | 521,366 |
+ | WIM (wimlib, LZMS solid) | 515,800 |
+ | tar.xz (xz, default) | 486,916 |
+ | tar.xz (xz, -9) | 486,904 |
+ | 7z (7-zip, default) | 484,700 |
+ | 7z (7-zip, -9) | 483,239 |
+ =====================================================
+
+Note: WIM does even better on directory trees containing duplicate files, which
+the Canterbury corpus doesn't have.
+
+ NTFS SUPPORT
+
+WIM images may contain data, such as alternate data streams and
+compression/encryption flags, that are best represented on the NTFS filesystem
+used on Windows. Also, WIM images may contain security descriptors which are
+specific to Windows and cannot be represented on other operating systems.
+wimlib handles this NTFS-specific or Windows-specific data in a
+platform-dependent way:
+
+ * In the Windows version of wimlib and wimlib-imagex, NTFS-specific and
+ Windows-specific data are supported natively.
+
+ * In the UNIX version of wimlib and wimlib-imagex, NTFS-specific and
+ Windows-specific data are ordinarily ignored; however, there is also special
+ support for capturing and extracting images directly to/from unmounted NTFS
+ volumes. This was made possible with the help of libntfs-3g from the
+ NTFS-3g project.
+
+For both platforms the code for NTFS capture and extraction is complete enough
+that it is possible to apply an image from the "install.wim" contained in recent
+Windows installation media (Vista or later) directly to an NTFS filesystem, and
+then boot Windows from it after preparing the Boot Configuration Data. In
addition, a Windows installation can be captured (or backed up) into a WIM file,
and then re-applied later.
- WINDOWS PE
+ WINDOWS PE
-A major use for this library is to create customized images of Windows PE, the
-Windows Preinstallation Environment, without having to rely on Windows. Windows
-PE is a lightweight version of Windows that can run entirely from memory and can
-be used to install Windows from local media or a network drive or perform
-maintenance. Windows PE is the operating system that runs when you boot from
+A major use for wimlib and wimlib-imagex is to create customized images of
+Windows PE, the Windows Preinstallation Environment, on either UNIX-like systems
+or Windows without having to rely on Microsoft's software and its restrictions
+and limitations.
+
+Windows PE is a lightweight version of Windows that can run entirely from memory
+and can be used to install Windows from local media or a network drive or
+perform maintenance. It is the operating system that runs when you boot from
the Windows installation media.
-You can find Windows PE on the installation DVD for Windows Vista, Windows 7, or
-Windows 8, in the file `sources/boot.wim'. Windows PE can also be found in the
-Windows Automated Installation Kit (WAIK), which is free to download from
-Microsoft, inside the `WinPE.cab' file, which you can extract if you install
-either the `cabextract' or `p7zip' programs.
+You can find Windows PE on the installation media for Windows (Vista or later)
+as the file `sources/boot.wim'. Windows PE can also be found in the Windows
+Automated Installation Kit (WAIK), which is free to download from Microsoft,
+inside the `WinPE.cab' file, which you can extract natively on Windows, or on
+UNIX-like systems if you install either the `cabextract' or `p7zip' programs.
In addition, Windows installations and recovery partitions frequently contain a
WIM containing an image of the Windows Recovery Environment, which is similar to
Windows PE.
- DEPENDENCIES
+A shell script `mkwinpeimg' is distributed with wimlib on UNIX-like systems to
+ease the process of creating and customizing a bootable Windows PE image.
+
+ DEPENDENCIES
+
+This section documents the dependencies of wimlib and the programs distributed
+with it, when building for a UNIX-like system from source. If you have
+downloaded the Windows binary distribution of wimlib and wimlib-imagex then all
+dependencies were already included and this section is irrelevant.
* libxml2 (required)
- This is a commonly used free library to read and write XML files. You
- likely already have it installed as a dependency for some other program.
- For more information see http://xmlsoft.org/.
-
-* libfuse (optional but highly recommended)
- Unless configured with --without-fuse, wimlib requires a non-ancient
- version of libfuse to be installed. Most GNU/Linux distributions
- already include this, but make sure you have the libfuse package
- installed, and also libfuse-dev if your distribution distributes header
- files separately. FUSE also requires a kernel module. If the kernel
- module is available it will automatically be loaded if you try to mount
- a WIM file. For more information see http://fuse.sourceforge.net/.
- FUSE is also available for FreeBSD.
-
-* libntfs-3g (optional but highly recommended)
- Unless configured with --without-ntfs-3g, wimlib requires the library
- and headers for libntfs-3g version 2011-4-12 or later to be installed.
- Versions dated 2010-3-6 and earlier do not work because they are missing
- the header xattrs.h (and the file xattrs.c, which contains functions we
- need).
+ This is a commonly used free library to read and write XML documents.
+ Almost all Linux distributions should include this; however, you may
+ need to install the header files, which might be in a package named
+ "libxml2-dev" or similar. For more information see http://xmlsoft.org/.
+
+* libfuse (optional but recommended)
+ Unless configured --without-fuse, wimlib requires a non-ancient version
+ of libfuse. Most Linux distributions already include this, but make
+ sure you have the libfuse package installed, and also libfuse-dev if
+ your distribution distributes header files separately. FUSE also
+ requires a kernel module. If the kernel module is available it should
+ automatically be loaded if you try to mount a WIM image. For more
+ information see http://fuse.sourceforge.net/.
+
+* libattr (optional but recommended)
+ Unless configured --without-fuse, wimlib also requires libattr. Almost
+ all Linux distributions should include this; however, you may need to
+ install the header files, which might be in a package named "attr-dev",
+ "libattr1-dev", or similar.
+
+* libntfs-3g (optional but recommended)
+ Unless configured --without-ntfs-3g, wimlib requires the library and
+ headers for libntfs-3g version 2011-4-12 or later to be installed.
* OpenSSL / libcrypto (optional)
- wimlib can use the SHA1 message digest code from OpenSSL instead of
- compiling in yet another SHA1 implementation. (See LICENSE section.)
+ wimlib can use the SHA-1 message digest implementation from libcrypto
+ (usually provided by OpenSSL) instead of compiling in yet another SHA-1
+ implementation.
* cdrkit (optional)
* mtools (optional)
* syslinux (optional)
* cabextract (optional)
The `mkwinpeimg' shell script will look for several other programs
- depending on what options are given to it. Depending on your GNU/Linux
+ depending on what options are given to it. Depending on your Linux
distribution, you may already have these programs installed, or they may
be in the software repository. Making an ISO filesystem requires
`mkisofs' from `cdrkit' (http://www.cdrkit.org). Making a disk image
(http://www.syslinux.org). Retrieving files from the Windows Automated
Installation Kit requires `cabextract' (http://www.cabextract.org.uk).
- CONFIGURATION
+ CONFIGURATION
-Besides the various well-known options, the following options can be passed to
-wimlib's `configure' script:
+This section documents the most important options that may be passed to the
+"configure" script when building from source:
--without-ntfs-3g
If libntfs-3g is not available or is not version 2011-4-12 or later,
wimlib can be built without it, in which case it will not be possible to
- apply or capture images directly to/from NTFS volumes.
+ capture or apply WIM images directly from/to NTFS volumes.
+
+ The default is --with-ntfs-3g when building for any UNIX-like system,
+ and --without-ntfs-3g when building for Windows.
--without-fuse
- If libfuse or the FUSE kernel module is not available, wimlib can be
- compiled with --without-fuse. This will remove the ability to mount and
- unmount WIM files.
+ The --without-fuse option disables support for mounting WIM images.
+ This removes dependencies on libfuse, librt, and libattr. The wimmount,
+ wimmountrw, and wimunmount commands will not work.
+
+ The default is --with-fuse when building for Linux, and --without-fuse
+ otherwise.
--without-libcrypto
- Build in functions for SHA1 rather than using external SHA1 functions
- from libcrypto (part of OpenSSL). The default is to use libcrypto if it
- is found on the system.
-
---enable-xattr, --disable-xattr
- Enable or disable support for the extended-attributes interface to NTFS
- alternate data streams in mounted WIMs. To support these, wimlib
- requires that the setxattr() function and the attr/xattr.h header are
- available. The default is to autodetect whether support is possible.
-
---disable-multithreaded-compression
- By default, data will be compressed using multiple threads when writing
- a WIM, unless only 1 processor is detected. Specify this option to
- disable support for this.
-
---enable-ssse3-sha1
- Use a very fast assembly language implementation of SHA1 from Intel.
- Only use this if the build target supports the SSSE3 instructions.
-
---disable-custom-memory-allocator
- If this option is given, a very small amount of space will be saved by
- removing support for the wimlib_set_memory_allocator() function. imagex
- will be unaffected.
-
---disable-verify-compression
- Unless this option is given, every time wimlib compresses a data block,
- it will decompress it into a temporary buffer and abort the program with
- an error message if the decompressed data does not exactly match the
- original data. This only makes compression about 10% slower. However,
- this checking can probably be safely disabled because there are no known
- bugs in the compression code, and the SHA1 message digest of every
- extracted file is checked anyway.
-
---disable-error-messages
- Save some space by removing all error messages from the library.
-
---disable-assertions
- Remove all assertions, even the ones that are included by default.
-
---enable-more-assertions
- Enable assertions that are not included by default.
-
---enable-debug
- Include debugging messages. Only use this option if you have found a
- bug in the library.
-
---enable-more-debug
- Include more debugging messages. Only use this option if you have found
- a bug in the library.
-
- PORTABILITY
-
-wimlib has mostly been developed and tested on x86_64 (64-bit) GNU/Linux.
-
-It has been tested on x86 (32-bit) GNU/Linux occasionally.
-
-wimlib may work on FreeBSD and Mac OS X. However, this is not well tested. If
-you do not have libntfs-3g 2011-4-12 or later available, you must configure
-wimlib with --without-ntfs-3g. On FreeBSD, before mounting a WIM you need to
-load the POSIX message queue module (run `kldload mqueuefs').
-
-The code pays attention to endianness, so it should work on big-endian
-architectures, but I've never tested this so do not expect it to work.
-
-There are no plans to port wimlib to Windows since the programming interface on
-Windows is very different and Microsoft's imagex.exe is already available.
-
- REFERENCES
-
-The WIM file format is specified in a document that can be found in the
-Microsoft Download Center. There is a similar document that specifies the LZX
-compression format, and a document that specifies the XPRESS compression format.
-However, many parts of these formats are poorly documented, and some parts have
-no documentation whatsoever. Some particularly poorly documented parts of the
-formats have had comments added in various places in the library. Please see
-the code and/or ask me if you have any questions about the WIM file format as it
-exists in reality and not as it exists in Microsoft's poorly written
-documentation.
-
-The code in ntfs-apply.c and ntfs-capture.c uses the NTFS-3g library, which is a
-library for reading and writing to NTFS filesystems (the filesystem used by
-recent versions of Windows). See
-http://www.tuxera.com/community/ntfs-3g-download/ for more information.
+ Build in functions for SHA-1 rather than using external SHA-1 functions
+ from libcrypto (usually provided by OpenSSL).
-lzx-decompress.c, the code to decompress WIM file resources that are compressed
-using LZX compression, is originally based on code from the cabextract project
-(http://www.cabextract.org.uk).
+ The default is to use libcrypto if it is found on your system.
-lzx-compress.c, the code to compress WIM file resources using LZX compression,
-is originally based on code written by Matthew Russotto (www.russotto.net/chm/).
+ PORTABILITY
-lz77.c, the code to find LZ77 matches (used for both XPRESS and LZX compression),
-is based on code from zlib.
+wimlib works on both UNIX-like systems (Linux, Mac OS X, FreeBSD, etc.) and
+Windows (XP and later).
-A very limited number of other free programs can handle some parts of the WIM
-file format. 7-zip is able to extract and create WIMs (as well as files in many
-other archive formats). However, wimlib is designed specifically to handle WIM
-files and provides features previously only available in Microsoft's imagex.exe,
-such as the ability to mount WIMs read-write as well as read-only, and the
-ability to create LZX or XPRESS compressed WIMs.
+As much code as possible is shared among all supported platforms, but there
+necessarily are some differences in what features are supported on each platform
+and how they are implemented. Most notable is that file tree scanning and
+extraction are implemented separately for Windows, UNIX, and UNIX (NTFS-3g
+mode), to ensure a fast and feature-rich implementation of each platform/mode.
-An earlier version of wimlib is being used to deploy Windows 7 from the Ultimate
-Deployment Appliance. For more information see
-http://www.ultimatedeployment.org/.
+wimlib is mainly used on x86 and x86_64 CPUs, but it should also work on a
+number of other GCC-supported 32-bit or 64-bit architectures. It has been
+tested on the ARM and MIPS architectures.
-You can see the documentation about Microsoft's version of the imagex program at
-http://technet.microsoft.com/en-us/library/cc749447(v=ws.10).aspx, so you can
-see how it compares to the version provided by this library.
+Currently, gcc and clang are the only supported compilers. A few nonstandard
+extensions are used in the code.
- GNU/Linux equivalents of WIM format
+ REFERENCES
-What's the equivalent way to capture the filesystem of a GNU/Linux operating
-system into an archive file? You have a few options:
+The WIM file format is partially specified in a document that can be found in
+the Microsoft Download Center. However, this document really only provides an
+overview of the format and is not a formal specification. It also does not
+cover later extensions of the format, such as solid resources.
-SquashFS:
- SquashFS (http://squashfs.sourceforge.net/) provides a compressed,
- read-only filesystem for Linux, and it's probably the closest equivalent
- of the WIM format and better designed. Although you can't mount
- SquashFS read-write, when wimlib does this for WIM files it's really an
- illusion since the WIM isn't actually modified until the image is
- unmounted. Multiple top-level images in SquashFS files are not
- supported, although nothing stops you from just putting each image in a
- separate directory.
+With regards to the supported compression formats:
-FSArchiver:
- FSArchiver (http://www.fsarchiver.org/Main_Page) is not widely used, but
- it appears to have some features quite similar to the WIM format.
+- Microsoft has official documentation for XPRESS that is of reasonable quality.
+- Microsoft has official documentation for LZX, but in two different documents,
+ neither of which is completely applicable to its use in the WIM format, and
+ the first of which contains multiple errors.
+- There does not seem to be any official documentation for LZMS, so my comments
+ and code in src/lzms_decompress.c may in fact be the best documentation
+ available for this particular compression format.
-Tar:
- The well-known tar format can usually capture a UNIX filesystem just
- fine, and compressing the tar file produces a good compression ratio
- (better than WIM, especially if using XZ compression), but there is no
- support for random access, file deduplication, multiple images per
- archive, or extended attributes.
+The algorithms used by wimlib's compression and decompression codecs are
+inspired by a variety of sources, including open source projects and computer
+science papers.
+
+The code in ntfs-3g_apply.c and ntfs-3g_capture.c uses the NTFS-3g library,
+which is a library for reading and writing to NTFS filesystems (the filesystem
+used by recent versions of Windows). See
+http://www.tuxera.com/community/ntfs-3g-download/ for more information.
-Zip:
- Zip shares some features with WIM but is not designed to store entire
- filesystems.
+A limited number of other free programs can handle some parts of the WIM
+file format:
-7z:
- The 7z format has some nice features but is unfortunately not designed
- with UNIX in mind.
+ * 7-zip is able to extract and create WIMs (as well as files in many
+ other archive formats). However, wimlib is designed specifically to handle
+ WIM files and provides features previously only available in Microsoft's
+ implementation, such as the ability to mount WIMs read-write as well as
+ read-only, the ability to create compressed WIMs, the correct handling of
+ security descriptors and hard links, support for LZMS compression, and
+ support for solid archives.
+ * ImagePyX (https://github.com/maxpat78/ImagePyX) is a Python program that
+ provides some capabilities of wimlib-imagex, with the help of external
+ compression codecs.
- MORE INFORMATION
+If you are looking for an archive format that provides features similar to WIM
+but was designed primarily for UNIX, you may want to consider SquashFS
+(http://squashfs.sourceforge.net/). However, you may find that wimlib works
+surprisingly well on UNIX. It will store hard links and symbolic links, and it
+has optional support for storing UNIX owners, groups, modes, and special files
+such as device nodes and FIFOs. Actually, I use it to back up my own files on
+Linux!
-See the manual pages for `imagex', the manual pages for the subcommands of
-`imagex', and the manual page for `mkwinpeimg'.
+ HISTORY
-As of version 0.5.0, wimlib's public API is documented. Doxygen is required to
-build the documentation. To build the documentation, run `configure', then
-enter the directory `doc' and run `doxygen'. The HTML documentation will be
-created in a directory named `html'.
+wimlib was originally a project started by Carl Thijssen for use on Linux in the
+Ultimate Deployment Appliance (http://www.ultimatedeployment.org/). Since then
+the code has been entirely rewritten and improved (main author: Eric Biggers).
+Windows support has been available since version 1.3.0 (March 2013). A list of
+version-to-version changes can be found in the NEWS file.
- LICENSE
+ LICENSE AND DISCLAIMER
-As of version 1.0.0, wimlib is released under the GNU GPL version 3.0 or later.
-This includes the files in the `programs' directory as well as the files in the
-`src' directory.
+See COPYING for information about the license.
wimlib is independently developed and does not contain any code, data, or files
copyrighted by Microsoft. It is not known to be affected by any patents.
-By default, wimlib will be linked to the system library "libcrypto", which
-probably will be OpenSSL. Some people believe that GPL code cannot be linked to
-OpenSSL without a linking exception. As far as I know, I cannot officially
-include a linking exception with the license of this library because several
-files could be considered derived works of code copyrighted by others. If you
-believe this to be a problem, configure with --without-libcrypto to avoid
-linking with OpenSSL. There is no difference in functionality--- there will
-just be stand-alone SHA1 message digest code built into the library.
-
- DISCLAIMER
-
-wimlib is experimental. Use Microsoft's `imagex.exe' if you want to make sure
-your WIM files are made correctly (but beware: Microsoft's version contains some
-bugs).
-
-Please submit a bug report (to ebiggers3@gmail.com) if you find a bug in wimlib.
+On UNIX-like systems, if you do not want wimlib to be dynamically linked with
+libcrypto (OpenSSL), configure with --without-libcrypto. This replaces the SHA1
+implementation with built-in code and there will be no difference in
+functionality.
-Some parts of the WIM file format are poorly documented or even completely
-undocumented, so I've just had to do the best I can to read and write WIMs that
-appear to be compatible with Microsoft's software.
+wimlib comes with no warranty whatsoever. Please submit a bug report (to
+ebiggers3@gmail.com) if you find a bug in wimlib and/or wimlib-imagex.
git://wimlib.net / wimlib / blobdiff