Add note in imagex-capture man page

[wimlib] / doc / imagex-capture.1.in

diff --git a/doc/imagex-capture.1.in b/doc/imagex-capture.1.in
index c29cf6059e257ae44f773b97c8bf7257d2c8cef4..a0927133c33f02d05d78d4fc94aa2e5c0d1bc33a 100644 (file)
--- a/doc/imagex-capture.1.in
+++ b/doc/imagex-capture.1.in
@@ -1,4 +1,4 @@
-.TH IMAGEX "1" "October 2012" "imagex (wimlib) wimlib @VERSION@" "User Commands"
+.TH IMAGEX "1" "November 2012" "imagex (wimlib) wimlib @VERSION@" "User Commands"

 .SH NAME
 imagex-capture, imagex-append \- Capture a WIM image from a directory tree
 
 .SH NAME
 imagex-capture, imagex-append \- Capture a WIM image from a directory tree
 


@@ -119,6 +119,12 @@ processors).  Note: if creating or appending to an uncompressed WIM, additional
 threads will not be used, regardless of this parameter, since no compression
 needs to be done in this case.
 .TP
 threads will not be used, regardless of this parameter, since no compression
 needs to be done in this case.
 .TP

+\fB--rebuild\fR
+For \fBimagex append\fR: rebuild the entire WIM rather than appending the new
+data to the end of it.  Rebuilding the WIM is slower, but will save a little bit
+of space that would otherwise be left as a hole in the WIM.  Also see \fBimagex
+optimize\fR.
+.TP

 \fB--flags\fR=\fIEDITIONID\fR
 Specify a string to use in the <FLAGS> element of the XML data for the new
 image.
 \fB--flags\fR=\fIEDITIONID\fR
 Specify a string to use in the <FLAGS> element of the XML data for the new
 image.


@@ -194,6 +200,24 @@ type, and \fBimagex\fR always enforces this.
 stream chunk size of 32768.  The only WIMs I've seen that are different from
 this are some pre-Vista WIMs that had a different version number.
 
 stream chunk size of 32768.  The only WIMs I've seen that are different from
 this are some pre-Vista WIMs that had a different version number.
 

+Unless \fB--rebuild\fR is specified, aborting an \fBimagex append\fR command
+mid-way through has a small chance of corrupting the WIM file.  However, a
+precaution is taken against this, so it should be very unlikely.  In the event
+of an aborted \fBimagex append\fR, \fBimagex optimize\fR may be run to remove
+extra data that may have been partially appended to the physical WIM file but
+not yet incorporated into the structure of the WIM.
+
+Capturing or appending an image happens in two main phases: (1) scanning the
+directory or NTFS volume to checksum all the files and determine the streams to
+be written, and (2) writing the new streams to the WIM file.  Streams are not
+stored in memory after (1), since there could easily be gigabytes of data;
+instead, they are read again during step (2); however, duplicate streams in the
+image, and streams already existing in any other image in the WIM, are not read
+again.  In the future, it may be possible to introduce the ability to capture an
+image with reading each file only one time, although this mode would have some
+limitations--- for example, a stream might be compressed only to be thrown away
+as a duplicate once it's been checksummed.
+

 .SH EXAMPLES
 Create a new WIM 'mywim.wim' from the directory 'somedir', using LZX compression and
 including an integrity table:
 .SH EXAMPLES
 Create a new WIM 'mywim.wim' from the directory 'somedir', using LZX compression and
 including an integrity table: