3 This is wimlib version 1.5.2 (November 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.
38 * Note: The Windows 8 WIMGAPI apparently adds a third format, LZMS, but it is
39 not documented and is incompatible with ImageX and Dism. It is unclear if
40 this new format is actually being used for anything.
44 wimlib itself is a C library, and it provides a documented public API (See:
45 http://wimlib.sourceforge.net) for other programs to use. However, it is also
46 distributed with a command-line program called "wimlib-imagex" that uses this
47 library to implement an imaging tool similar to Microsoft's ImageX.
48 wimlib-imagex supports almost all the capabilities of Microsoft's ImageX as well
49 as additional capabilities. wimlib-imagex works on both UNIX-like systems and
50 Windows, although some features differ between the platforms.
52 Run `wimlib-imagex' with no arguments to see an overview of the available
53 commands and their syntax. For additional documentation:
55 * If you have installed wimlib-imagex on a UNIX-like system, you will find
56 further documentation in the man pages; run `man wimlib-imagex' to get
59 * If you have downloaded the Windows binary distribution, you will find the
60 documentation for wimlib-imagex in PDF format in the "doc" directory,
61 ready for viewing with any PDF viewer. Please note that although the PDF
62 files are converted from UNIX-style "man pages", they do document
63 Windows-specific behavior when appropriate.
67 wimlib (and wimlib-imagex) can create XPRESS or LZX compressed WIM archives.
68 Currently, the XPRESS compression ratio is slightly better than that provided by
69 Microsoft's software, while by default the LZX compression ratio is approaching
70 that of Microsoft's software but is not quite there yet. Running time is as
71 good as or better than Microsoft's software, especially with multithreaded
72 compression, available in wimlib v1.1.0 and later.
74 The following tables compare the compression ratio and performance for creating
75 a compressed x86_64 Windows PE image. Note: these timings were done on Windows
76 7 so that the times would be fully comparable; however, wimlib-imagex may have
77 even better performance on Linux.
81 XPRESS Compression LZX Compression
82 wimlib-imagex (v1.4.0): 165,301,379 bytes 155,254,385 bytes
83 Microsoft imagex.exe: 167,212,939 bytes 149,973,212 bytes
85 Table 2. Time to create WIM
87 XPRESS Compression LZX Compression
88 wimlib-imagex (v1.4.0, 2 threads): 18 sec 51 sec
89 Microsoft imagex.exe: 25 sec 93 sec
91 The above LZX values are using the default LZX compressor. wimlib v1.5.2
92 introduced a new experimental LZX compressor which can be enabled by passing
93 '--compress-slow' to `wimlib-imagex capture' or `wimlib-imagex optimize'. This
94 compressor is much slower but compresses the data slightly more --- currently
95 usually to within a fraction of a percent of the results from imagex.exe.
99 WIM images may contain data, such as alternate data streams and
100 compression/encryption flags, that are best represented on the NTFS filesystem
101 used on Windows. Also, WIM images may contain security descriptors which are
102 specific to Windows and cannot be represented on other operating systems.
103 wimlib handles this NTFS-specific or Windows-specific data in a
104 platform-dependent way:
106 * In the Windows version of wimlib and wimlib-imagex, NTFS-specific and
107 Windows-specific data are supported natively.
109 * In the UNIX version of wimlib and wimlib-imagex, NTFS-specific and
110 Windows-specific data are ordinarily ignored; however, there is also special
111 support for capturing and extracting images directly to/from unmounted NTFS
112 volumes. This was made possible with the help of libntfs-3g from the
115 For both platforms the code for NTFS capture and extraction is complete enough
116 that it is possible to apply an image from the "install.wim" contained in recent
117 Windows installation media (Vista, Windows 7, or Windows 8) directly to a NTFS
118 filesystem, and then boot Windows from it after preparing the Boot Configuration
119 Data. In addition, a Windows installation can be captured (or backed up) into a
120 WIM file, and then re-applied later.
124 A major use for wimlib and wimlib-imagex is to create customized images of
125 Windows PE, the Windows Preinstallation Environment, on either UNIX-like systems
126 or Windows without having to rely on Microsoft's software and its restrictions
129 Windows PE is a lightweight version of Windows that can run entirely from memory
130 and can be used to install Windows from local media or a network drive or
131 perform maintenance. It is the operating system that runs when you boot from
132 the Windows installation media.
134 You can find Windows PE on the installation DVD for Windows Vista, Windows 7, or
135 Windows 8, in the file `sources/boot.wim'. Windows PE can also be found in the
136 Windows Automated Installation Kit (WAIK), which is free to download from
137 Microsoft, inside the `WinPE.cab' file, which you can extract natively on
138 Windows, or on UNIX-like systems if you install either the `cabextract' or
141 In addition, Windows installations and recovery partitions frequently contain a
142 WIM containing an image of the Windows Recovery Environment, which is similar to
145 A shell script `mkwinpeimg' is distributed with wimlib on UNIX-like systems to
146 ease the process of creating and customizing a bootable Windows PE image.
150 This section documents the dependencies of wimlib and the programs distributed
151 with it, when building for a UNIX-like system from source. If you have
152 downloaded the Windows binary distribution of wimlib and wimlib-imagex then all
153 dependencies were already included and this section is irrelevant.
156 This is a commonly used free library to read and write XML files. You
157 likely already have it installed as a dependency for some other program.
158 For more information see http://xmlsoft.org/.
160 * libfuse (optional but highly recommended)
161 Unless configured with --without-fuse, wimlib requires a non-ancient
162 version of libfuse to be installed. Most Linux distributions already
163 include this, but make sure you have the libfuse package installed, and
164 also libfuse-dev if your distribution distributes header files
165 separately. FUSE also requires a kernel module. If the kernel module
166 is available it will automatically be loaded if you try to mount a WIM
167 file. For more information see http://fuse.sourceforge.net/. FUSE is
168 also available for FreeBSD.
170 * libntfs-3g (optional but highly recommended)
171 Unless configured with --without-ntfs-3g, wimlib requires the library
172 and headers for libntfs-3g version 2011-4-12 or later to be installed.
173 Versions dated 2010-3-6 and earlier do not work because they are missing
174 the header xattrs.h (and the file xattrs.c, which contains functions we
175 need). libntfs-3g version 2013-1-13 is compatible only with wimlib
178 * OpenSSL / libcrypto (optional)
179 wimlib can use the SHA1 message digest code from OpenSSL instead of
180 compiling in yet another SHA1 implementation. (See LICENSE section.)
184 * syslinux (optional)
185 * cabextract (optional)
186 The `mkwinpeimg' shell script will look for several other programs
187 depending on what options are given to it. Depending on your Linux
188 distribution, you may already have these programs installed, or they may
189 be in the software repository. Making an ISO filesystem requires
190 `mkisofs' from `cdrkit' (http://www.cdrkit.org). Making a disk image
191 requires `mtools' (http://www.gnu.org/software/mtools) and `syslinux'
192 (http://www.syslinux.org). Retrieving files from the Windows Automated
193 Installation Kit requires `cabextract' (http://www.cabextract.org.uk).
197 This section documents the most important options that may be passed to the
198 "configure" script when building from source:
201 If libntfs-3g is not available or is not version 2011-4-12 or later,
202 wimlib can be built without it, in which case it will not be possible to
203 apply or capture images directly to/from NTFS volumes.
206 If libfuse or the FUSE kernel module is not available, wimlib can be
207 compiled with --without-fuse. This will remove the ability to mount and
211 Build in functions for SHA1 rather than using external SHA1 functions
212 from libcrypto (part of OpenSSL). The default is to use libcrypto if it
213 is found on the system.
215 --enable-xattr, --disable-xattr
216 Enable or disable support for the extended-attributes interface to NTFS
217 alternate data streams in mounted WIMs. To support these, wimlib
218 requires that the setxattr() function and the attr/xattr.h header are
219 available. The default is to autodetect whether support is possible.
221 --disable-multithreaded-compression
222 By default, data will be compressed using multiple threads when writing
223 a WIM, unless only 1 processor is detected. Specify this option to
224 disable support for this.
227 Use a very fast assembly language implementation of SHA1 from Intel.
228 Only use this if the build target supports the SSSE3 instructions.
230 --disable-error-messages
231 Save some space by removing all error messages from the library.
234 Remove assertions included by default.
238 wimlib has primarily been tested on Linux and Windows (primarily Windows 7, but
239 also Windows XP and Windows 8).
241 wimlib may work on FreeBSD and Mac OS X. However, this is not well tested. If
242 you do not have libntfs-3g 2011-4-12 or later available, you must configure
243 wimlib with --without-ntfs-3g. On FreeBSD, before mounting a WIM you need to
244 load the POSIX message queue module (run `kldload mqueuefs').
246 The code has primarily been tested on x86 and x86_64 CPUs, but it's written to
247 be portable to other architectures and I've also tested it on ARM. However,
248 although the code is written to correctly deal with endianness, it has not yet
249 actually been tested on a big-endian architecture.
253 The WIM file format is specified in a document that can be found in the
254 Microsoft Download Center. There is a similar document that specifies the LZX
255 compression format, and a document that specifies the XPRESS compression format.
256 However, many parts of these formats are poorly documented, and some parts have
257 no documentation whatsoever. Some particularly poorly documented parts of the
258 formats have had comments added in various places in the library code. Please
259 see the code and/or ask me if you have any questions about the WIM file format
260 as it exists in reality and not as it exists in Microsoft's poorly written
263 The code in ntfs-3g_apply.c and ntfs-3g_capture.c uses the NTFS-3g library,
264 which is a library for reading and writing to NTFS filesystems (the filesystem
265 used by recent versions of Windows). See
266 http://www.tuxera.com/community/ntfs-3g-download/ for more information.
268 lzx-decompress.c, the code to decompress WIM file resources that are compressed
269 using LZX compression, was originally based on code from the cabextract project
270 (http://www.cabextract.org.uk) but has been rewritten.
272 lzx-compress.c, the code to compress WIM file resources using LZX compression,
273 was originally based on code written by Matthew Russotto (www.russotto.net/chm/)
274 but has been rewritten.
276 lz77.c, the code to find LZ77 matches (used for both XPRESS and LZX
277 compression), is based on code from zlib but has been rewritten.
279 A limited number of other free programs can handle some parts of the WIM
282 * 7-zip is able to extract and create WIMs (as well as files in many
283 other archive formats). However, wimlib is designed specifically to handle
284 WIM files and provides features previously only available in Microsoft's
285 imagex.exe, such as the ability to mount WIMs read-write as well as
286 read-only, the ability to create LZX or XPRESS compressed WIMs, and the
287 correct handling of security descriptors and hard links.
288 * ImagePyX (https://github.com/maxpat78/ImagePyX) is a Python program that
289 provides similar capabilities to wimlib-imagex. One thing to note, though,
290 is that it does not support compression and decompression by itself, but
291 instead relies on external native code, such as the codecs from wimlib.
293 A very early version of wimlib is being used to deploy Windows 7 from the
294 Ultimate Deployment Appliance. For more information see
295 http://www.ultimatedeployment.org/.
297 You can see the documentation about Microsoft's version of ImageX at
298 http://technet.microsoft.com/en-us/library/cc749447(v=ws.10).aspx, so you can
299 see how it compares to wimlib-imagex.
301 If you are looking for a UNIX archive format that provides features similar to
302 WIM, I recommend you take a look at SquashFS (http://squashfs.sourceforge.net/).
306 As of version 1.0.0, wimlib and all programs and scripts distributed with it are
307 released under the GNU GPL version 3.0 or later.
309 wimlib is independently developed and does not contain any code, data, or files
310 copyrighted by Microsoft. It is not known to be affected by any patents.
312 On UNIX-like systems, if you do not want wimlib to be dynamically linked with
313 libcrypto (OpenSSL), configure with --without-libcrypto. This replaces the SHA1
314 implementation with built-in code and there will be no difference in
319 wimlib comes with no warranty whatsoever. Use Microsoft's `imagex.exe' if you
320 want to make sure your WIM files are made "correctly" (but beware: Microsoft's
321 version contains some bugs).
323 Please submit a bug report (to ebiggers3@gmail.com) if you find a bug in wimlib
324 and/or wimlib-imagex.
326 Be aware that some parts of the WIM file format are poorly documented or even
327 completely undocumented, so I've just had to do the best I can to read and write
328 WIMs that appear to be compatible with Microsoft's software.
git://wimlib.net / wimlib / blob