+++ /dev/null
-@c This is part of the paxutils manual.
-@c Copyright (C) 2005, 2007 Free Software Foundation, Inc.
-@c Written by Sergey Poznyakoff
-@c This file is distributed under GFDL 1.1 or any later version
-@c published by the Free Software Foundation.
-
- A @dfn{snapshot file} (or @dfn{directory file}) is created during
-incremental backups (@pxref{Incremental Dumps}). It
-contains the status of the file system at the time of the dump and is
-used to determine which files were modified since the last backup.
-
- @GNUTAR{} version @value{VERSION} supports three snapshot file
-formats. The first format, called @dfn{format 0}, is the one used by
-@GNUTAR{} versions up to 1.15.1. The second format, called @dfn{format
-1} is an extended version of this format, that contains more metadata
-and allows for further extensions. It was used by version
-1.15.1. Starting from version 1.16 and up to @value{VERSION}, the
-@dfn{format 2} is used.
-
- @GNUTAR{} is able to read all three formats, but will create
-snapshots only in format 2.
-
- This appendix describes all three formats in detail.
-
-@enumerate 0
-@cindex format 0, snapshot file
-@cindex snapshot file, format 0
-@item
- @samp{Format 0} snapshot file begins with a line containing a
-decimal number that represents a @acronym{UNIX} timestamp of the
-beginning of the last archivation. This line is followed by directory
-metadata descriptions, one per line. Each description has the
-following format:
-
-@smallexample
-@var{nfs}@var{dev} @var{inode} @var{name}
-@end smallexample
-
-@noindent
-where:
-
-@table @var
-@item nfs
-A single plus character (@samp{+}), if this directory is located on
-an @acronym{NFS}-mounted partition, or a single space otherwise;
-
-@item dev
-Device number of the directory;
-
-@item inode
-I-node number of the directory;
-
-@item name
-Name of the directory. Any special characters (white-space,
-backslashes, etc.) are quoted.
-@end table
-
-@cindex format 1, snapshot file
-@cindex snapshot file, format 1
-@item
- @samp{Format 1} snapshot file begins with a line specifying the
-format of the file. This line has the following structure:
-
-@smallexample
-@samp{GNU tar-}@var{tar-version}@samp{-}@var{incr-format-version}
-@end smallexample
-
-@noindent
-where @var{tar-version} is the version number of @GNUTAR{}
-implementation that created this snapshot, and
-@var{incr-format-version} is the version number of the snapshot format
-(in this case @samp{1}).
-
- Next line contains two decimal numbers, representing the
-time of the last backup. First number is the number of seconds, the
-second one is the number of nanoseconds, since the beginning of the
-epoch.
-
- Lines that follow contain directory metadata, one line per
-directory. Each line is formatted as follows:
-
-@smallexample
-[@var{nfs}]@var{mtime-sec} @var{mtime-nsec} @var{dev} @var{inode} @var{name}
-@end smallexample
-
-@noindent
-where @var{mtime-sec} and @var{mtime-nsec} represent last
-modification time of this directory with nanosecond precision;
-@var{nfs}, @var{dev}, @var{inode} and @var{name} have the same meaning
-as with @samp{format 0}.
-
-@cindex format 2, snapshot file
-@cindex snapshot file, format 2
-@item
-@FIXME{}
- A snapshot file begins with a format identifier, as described for
-version 1, e.g.:
-
-@smallexample
-GNU tar-@value{VERSION}-2
-@end smallexample
-
- This line is followed by newline. Rest of file consists of
-records, separated by null (@acronym{ASCII} 0)
-characters. Thus, in contrast to the previous formats, format 2
-snapshot is a binary file.
-
- First two records are decimal numbers, representing the
-time of the last backup. First number is the number of seconds, the
-second one is the number of nanoseconds, since the beginning of the
-epoch. These are followed by arbitrary number of directory records.
-
- Each @dfn{directory record} contains a set of metadata describing a
-particular directory. Parts of a directory record are delimited with
-@acronym{ASCII} 0 characters. The following table describes each
-part. The @dfn{Number} type in this table stands for a decimal number
-in @acronym{ASCII} notation.
-
-@multitable @columnfractions 0.2 0.2 0.6
-@headitem Field @tab Type @tab Description
-@item nfs @tab Character @tab @samp{1} if the directory is located on
-an @acronym{NFS}-mounted partition, or @samp{0} otherwise;
-@item mtime-sec @tab Number @tab Modification time, seconds;
-@item mtime-nano @tab Number @tab Modification time, nanoseconds;
-@item dev-no @tab Number @tab Device number;
-@item i-no @tab Number @tab I-node number;
-@item name @tab String @tab Directory name; In contrast to the
-previous versions it is not quoted.
-@item contents @tab Dumpdir @tab Contents of the directory;
-@xref{Dumpdir}, for a description of its format.
-@item
-@end multitable
-
- Dumpdirs stored in snapshot files contain only records of types
-@samp{Y}, @samp{N} and @samp{D}.
-
-@end enumerate
-
-@c End of snapshot.texi
-
-
projects / tar / blobdiff