INTRODUCTION
-This is wimlib version 1.5.2 (November 2013). wimlib is a C library for creating,
-modifying, extracting, and mounting files in the Windows Imaging Format (WIM
-files). These files are normally created by using the `imagex.exe' utility on
-Windows, but wimlib is distributed with a free implementation of ImageX called
-"wimlib-imagex" for both UNIX-like systems and Windows.
+This is wimlib version 1.5.3 (December 2013). wimlib is a C library for
+creating, modifying, extracting, and mounting files in the Windows Imaging
+Format (WIM files). These files are normally created using the ImageX
+(imagex.exe) or Dism (Dism.exe) utilities on Windows, but wimlib is distributed
+with a free implementation of ImageX called "wimlib-imagex" for both UNIX-like
+systems and Windows.
INSTALLATION
COMPRESSION RATIO
wimlib (and wimlib-imagex) can create XPRESS or LZX compressed WIM archives.
-Currently, the XPRESS compression ratio is slightly better than that provided by
-Microsoft's software, while by default 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 x86_64 Windows PE image. Note: these timings were done on Windows
-7 so that the times would be fully comparable; however, wimlib-imagex may have
-even better performance on Linux.
+so that the times would be fully comparable; however, wimlib may have even
+better performance on other operating systems such as Linux. Timings were done
+with 2 CPUs available, both of which automatically are used by wimlib for both
+XPRESS and LZX, and also by imagex.exe but apparently only for LZX.
Table 1. WIM size
XPRESS Compression LZX Compression
- wimlib-imagex (v1.4.0): 165,301,379 bytes 155,254,385 bytes
- Microsoft imagex.exe: 167,212,939 bytes 149,973,212 bytes
+ wimlib-imagex (v1.5.3): 207,444,390 bytes 188,106,091 bytes
+ Microsoft imagex.exe (Windows 7): 209,960,209 bytes 188,224,481 bytes
Table 2. Time to create WIM
XPRESS Compression LZX Compression
- wimlib-imagex (v1.4.0, 2 threads): 18 sec 51 sec
- Microsoft imagex.exe: 25 sec 93 sec
-
-The above LZX values are using the default LZX compressor. wimlib v1.5.2
-introduced a new experimental LZX compressor which can be enabled by passing
-'--compress-slow' to `wimlib-imagex capture' or `wimlib-imagex optimize'. This
-compressor is much slower but compresses the data slightly more --- currently
-usually to within a fraction of a percent of the results from imagex.exe.
+ wimlib-imagex (v1.5.3): 73 sec 202 sec
+ Microsoft imagex.exe (Windows 7): 90 sec 149 sec
+
+The above LZX data are using explicitly specified maximum compression
+('--compress=maximum') as of wimlib v1.5.3. If `wimlib-imagex capture' or
+`wimlib-imagex capture' is instead run with no '--compress' argument, then a
+faster LZX compressor is used; it will produce results in between those given
+for XPRESS and LZX above.
+
+Note: if the absolute maximum (but still compatible) compression ratio is
+desired, `wimlib-imagex optimize WIMFILE --recompress --compress-slow' on one of
+the above LZX-compressed WIMs produces a WIM of 187,089,943 bytes in about 400
+seconds.
NTFS SUPPORT
git://wimlib.net / wimlib / blobdiff