3 This is wimlib version 1.5.0 (August 2013). wimlib is a C library for creating,
4 modifying, extracting, and mounting files in the Windows Imaging Format (WIM
5 files). These files are normally created by using the `imagex.exe' utility on
6 Windows, but wimlib is distributed with a free implementation of ImageX called
7 "wimlib-imagex" for both UNIX-like systems and Windows.
11 To install wimlib and wimlib-imagex on Windows you simply need to download and
12 extract the ZIP file containing the latest binaries from the SourceForge page
13 (http://sourceforge.net/projects/wimlib/), which you may have already done.
15 To install wimlib and wimlib-imagex on UNIX-like systems (with Linux being the
16 primary supported and tested platform), you must compile the source code, which
17 is also available at http://sourceforge.net/projects/wimlib/. Alternatively,
18 check if a package has been prepared for your Linux distribution. Example files
19 for Debian and RPM packaging are in the debian/ and rpm/ directories.
23 A Windows Imaging (WIM) file is an archive designed primarily for archiving
24 Windows filesystems. However, it can be used on other platforms as well, with
25 some limitations. Like some other archive formats such as ZIP, files in WIM
26 archives may be compressed. WIM files support two compression formats: LZX and
27 XPRESS. Both are supported by wimlib.
29 A WIM file consists of one or more "images". Each image is an independent
30 top-level directory structure and is logically separate from all other images in
31 the WIM. Each image has a name as well as a 1-based index in the WIM file. To
32 save space, WIM archives automatically combine all duplicate files across all
35 A WIM file may be either stand-alone or split into multiple parts. Split WIMs
36 are read-only and cannot be modified.
40 wimlib itself is a C library, and it provides a documented public API (See:
41 http://wimlib.sourceforge.net) for other programs to use. However, it is also
42 distributed with a command-line program called "wimlib-imagex" that uses this
43 library to implement an imaging tool similar to Microsoft's ImageX.
44 wimlib-imagex supports almost all the capabilities of Microsoft's ImageX as well
45 as additional capabilities. wimlib-imagex works on both UNIX-like systems and
46 Windows, although some features differ between the platforms.
48 Run `wimlib-imagex' with no arguments to see an overview of the available
49 commands and their syntax. For additional documentation:
51 * If you have installed wimlib-imagex on a UNIX-like system, you will find
52 further documentation in the man pages; run `man wimlib-imagex' to get
55 * If you have downloaded the Windows binary distribution, you will find the
56 documentation for wimlib-imagex in PDF format in the "doc" directory,
57 ready for viewing with any PDF viewer. Please note that although the PDF
58 files are converted from UNIX-style "man pages", they do document
59 Windows-specific behavior when appropriate.
63 wimlib (and wimlib-imagex) can create XPRESS or LZX compressed WIM archives.
64 Currently, the XPRESS compression ratio is slightly better than that provided by
65 Microsoft's software, while the LZX compression ratio is approaching that of
66 Microsoft's software but is not quite there yet. Running time is as good as or
67 better than Microsoft's software, especially with multithreaded compression,
68 available in wimlib v1.1.0 and later.
70 The following tables compare the compression ratio and performance for creating
71 a compressed x86_64 Windows PE image. Note: these timings were done on Windows
72 7 so that the times would be fully comparable; however, wimlib-imagex may have
73 even better performance on Linux.
77 XPRESS Compression LZX Compression
78 wimlib-imagex (v1.4.0): 165,301,379 bytes 155,254,385 bytes
79 Microsoft imagex.exe: 167,212,939 bytes 149,973,212 bytes
81 Table 2. Time to create WIM
83 XPRESS Compression LZX Compression
84 wimlib-imagex (v1.4.0, 2 threads): 18 sec 51 sec
85 Microsoft imagex.exe: 25 sec 93 sec
89 WIM images may contain data, such as alternate data streams and
90 compression/encryption flags, that are best represented on the NTFS filesystem
91 used on Windows. Also, WIM images may contain security descriptors which are
92 specific to Windows and cannot be represented on other operating systems.
93 wimlib handles this NTFS-specific or Windows-specific data in a
94 platform-dependent way:
96 * In the Windows version of wimlib and wimlib-imagex, NTFS-specific and
97 Windows-specific data are supported natively.
99 * In the UNIX version of wimlib and wimlib-imagex, NTFS-specific and
100 Windows-specific data are ordinarily ignored; however, there is also special
101 support for capturing and extracting images directly to/from unmounted NTFS
102 volumes. This was made possible with the help of libntfs-3g from the
105 For both platforms the code for NTFS capture and extraction is complete enough
106 that it is possible to apply an image from the "install.wim" contained in recent
107 Windows installation media (Vista, Windows 7, or Windows 8) directly to a NTFS
108 filesystem, and then boot Windows from it after preparing the Boot Configuration
109 Data. In addition, a Windows installation can be captured (or backed up) into a
110 WIM file, and then re-applied later.
114 A major use for wimlib and wimlib-imagex is to create customized images of
115 Windows PE, the Windows Preinstallation Environment, on either UNIX-like systems
116 or Windows without having to rely on Microsoft's software and its restrictions
119 Windows PE is a lightweight version of Windows that can run entirely from memory
120 and can be used to install Windows from local media or a network drive or
121 perform maintenance. It is the operating system that runs when you boot from
122 the Windows installation media.
124 You can find Windows PE on the installation DVD for Windows Vista, Windows 7, or
125 Windows 8, in the file `sources/boot.wim'. Windows PE can also be found in the
126 Windows Automated Installation Kit (WAIK), which is free to download from
127 Microsoft, inside the `WinPE.cab' file, which you can extract natively on
128 Windows, or on UNIX-like systems if you install either the `cabextract' or
131 In addition, Windows installations and recovery partitions frequently contain a
132 WIM containing an image of the Windows Recovery Environment, which is similar to
135 A shell script `mkwinpeimg' is distributed with wimlib on UNIX-like systems to
136 ease the process of creating and customizing a bootable Windows PE image.
140 This section documents the dependencies of wimlib and the programs distributed
141 with it, when building for a UNIX-like system from source. If you have
142 downloaded the Windows binary distribution of wimlib and wimlib-imagex then all
143 dependencies were already included and this section is irrelevant.
146 This is a commonly used free library to read and write XML files. You
147 likely already have it installed as a dependency for some other program.
148 For more information see http://xmlsoft.org/.
150 * libfuse (optional but highly recommended)
151 Unless configured with --without-fuse, wimlib requires a non-ancient
152 version of libfuse to be installed. Most Linux distributions already
153 include this, but make sure you have the libfuse package installed, and
154 also libfuse-dev if your distribution distributes header files
155 separately. FUSE also requires a kernel module. If the kernel module
156 is available it will automatically be loaded if you try to mount a WIM
157 file. For more information see http://fuse.sourceforge.net/. FUSE is
158 also available for FreeBSD.
160 * libntfs-3g (optional but highly recommended)
161 Unless configured with --without-ntfs-3g, wimlib requires the library
162 and headers for libntfs-3g version 2011-4-12 or later to be installed.
163 Versions dated 2010-3-6 and earlier do not work because they are missing
164 the header xattrs.h (and the file xattrs.c, which contains functions we
165 need). libntfs-3g version 2013-1-13 is compatible only with wimlib
168 * OpenSSL / libcrypto (optional)
169 wimlib can use the SHA1 message digest code from OpenSSL instead of
170 compiling in yet another SHA1 implementation. (See LICENSE section.)
174 * syslinux (optional)
175 * cabextract (optional)
176 The `mkwinpeimg' shell script will look for several other programs
177 depending on what options are given to it. Depending on your Linux
178 distribution, you may already have these programs installed, or they may
179 be in the software repository. Making an ISO filesystem requires
180 `mkisofs' from `cdrkit' (http://www.cdrkit.org). Making a disk image
181 requires `mtools' (http://www.gnu.org/software/mtools) and `syslinux'
182 (http://www.syslinux.org). Retrieving files from the Windows Automated
183 Installation Kit requires `cabextract' (http://www.cabextract.org.uk).
187 This section documents the most important options that may be passed to the
188 "configure" script when building from source:
191 If libntfs-3g is not available or is not version 2011-4-12 or later,
192 wimlib can be built without it, in which case it will not be possible to
193 apply or capture images directly to/from NTFS volumes.
196 If libfuse or the FUSE kernel module is not available, wimlib can be
197 compiled with --without-fuse. This will remove the ability to mount and
201 Build in functions for SHA1 rather than using external SHA1 functions
202 from libcrypto (part of OpenSSL). The default is to use libcrypto if it
203 is found on the system.
205 --enable-xattr, --disable-xattr
206 Enable or disable support for the extended-attributes interface to NTFS
207 alternate data streams in mounted WIMs. To support these, wimlib
208 requires that the setxattr() function and the attr/xattr.h header are
209 available. The default is to autodetect whether support is possible.
211 --disable-multithreaded-compression
212 By default, data will be compressed using multiple threads when writing
213 a WIM, unless only 1 processor is detected. Specify this option to
214 disable support for this.
217 Use a very fast assembly language implementation of SHA1 from Intel.
218 Only use this if the build target supports the SSSE3 instructions.
220 --disable-error-messages
221 Save some space by removing all error messages from the library.
224 Remove assertions included by default.
228 wimlib has primarily been tested on Linux and Windows (primarily Windows 7, but
229 also Windows XP and Windows 8).
231 wimlib may work on FreeBSD and Mac OS X. However, this is not well tested. If
232 you do not have libntfs-3g 2011-4-12 or later available, you must configure
233 wimlib with --without-ntfs-3g. On FreeBSD, before mounting a WIM you need to
234 load the POSIX message queue module (run `kldload mqueuefs').
236 The code has primarily been tested on x86 and x86_64 CPUs, but it's written to
237 be portable to other architectures and I've also tested it on ARM. However,
238 although the code is written to correctly deal with endianness, it has not yet
239 actually been tested on a big-endian architecture.
243 The WIM file format is specified in a document that can be found in the
244 Microsoft Download Center. There is a similar document that specifies the LZX
245 compression format, and a document that specifies the XPRESS compression format.
246 However, many parts of these formats are poorly documented, and some parts have
247 no documentation whatsoever. Some particularly poorly documented parts of the
248 formats have had comments added in various places in the library code. Please
249 see the code and/or ask me if you have any questions about the WIM file format
250 as it exists in reality and not as it exists in Microsoft's poorly written
253 The code in ntfs-3g_apply.c and ntfs-3g_capture.c uses the NTFS-3g library,
254 which is a library for reading and writing to NTFS filesystems (the filesystem
255 used by recent versions of Windows). See
256 http://www.tuxera.com/community/ntfs-3g-download/ for more information.
258 lzx-decompress.c, the code to decompress WIM file resources that are compressed
259 using LZX compression, was originally based on code from the cabextract project
260 (http://www.cabextract.org.uk) but has been rewritten.
262 lzx-compress.c, the code to compress WIM file resources using LZX compression,
263 was originally based on code written by Matthew Russotto (www.russotto.net/chm/)
264 but has been rewritten.
266 lz77.c, the code to find LZ77 matches (used for both XPRESS and LZX
267 compression), is based on code from zlib but has been rewritten.
269 A limited number of other free programs can handle some parts of the WIM
272 * 7-zip is able to extract and create WIMs (as well as files in many
273 other archive formats). However, wimlib is designed specifically to handle
274 WIM files and provides features previously only available in Microsoft's
275 imagex.exe, such as the ability to mount WIMs read-write as well as
276 read-only, the ability to create LZX or XPRESS compressed WIMs, and the
277 correct handling of security descriptors and hard links.
278 * ImagePyX (https://github.com/maxpat78/ImagePyX) is a Python program that
279 provides similar capabilities to wimlib-imagex. One thing to note, though,
280 is that it does not support compression and decompression by itself, but
281 instead relies on external native code, such as the codecs from wimlib.
283 A very early version of wimlib is being used to deploy Windows 7 from the
284 Ultimate Deployment Appliance. For more information see
285 http://www.ultimatedeployment.org/.
287 You can see the documentation about Microsoft's version of ImageX at
288 http://technet.microsoft.com/en-us/library/cc749447(v=ws.10).aspx, so you can
289 see how it compares to wimlib-imagex.
291 If you are looking for a UNIX archive format that provides features similar to
292 WIM, I recommend you take a look at SquashFS (http://squashfs.sourceforge.net/).
296 As of version 1.0.0, wimlib and all programs and scripts distributed with it are
297 released under the GNU GPL version 3.0 or later.
299 wimlib is independently developed and does not contain any code, data, or files
300 copyrighted by Microsoft. It is not known to be affected by any patents.
302 On UNIX-like systems, if you do not want wimlib to be dynamically linked with
303 libcrypto (OpenSSL), configure with --without-libcrypto. This replaces the SHA1
304 implementation with built-in code and there will be no difference in
309 wimlib comes with no warranty whatsoever. Use Microsoft's `imagex.exe' if you
310 want to make sure your WIM files are made "correctly" (but beware: Microsoft's
311 version contains some bugs).
313 Please submit a bug report (to ebiggers3@gmail.com) if you find a bug in wimlib
314 and/or wimlib-imagex.
316 Be aware that some parts of the WIM file format are poorly documented or even
317 completely undocumented, so I've just had to do the best I can to read and write
318 WIMs that appear to be compatible with Microsoft's software.
git://wimlib.net / wimlib / blob