NAME

       af_archive -- format of archive files in the Attribute Filesystem

SYNOPSIS

       #include <atfs.h>
       #include <afsys.h>

DESCRIPTION

       AtFS  archive  files  are  used to store the data and attributes of non-busy ASOs.  Beside
       these, some attributes (including all user defined attributes) of busy ASOs are stored  in
       AtFS archive files.

       AtFS  maintains  two archive files for each line of development, one to hold the standard-
       and the user defined attributes and the other to hold the data and  change  notes.   These
       files  are  stored  either in a subdirectory named AtFS or in a explicitly named directory
       somewhere in your file system.  The two archive files are named
            Attr/<filename>          (attributes) and
            Data/<filename>          (data).

       This manual contains a short, exemplary description of the archive structure.  All data in
       AtFS-archives  are stored as ASCII-strings.  The archives contain keywords and keyletters.
       These are set in boldface in the following  description.   Strings  of  the  form  <field>
       describe the purpose of the appropriate field in the archive.

       Here's the structure (the attributes file first):

                                            The Header, ...

       ^BARHD   <archive_format_version>   <no_of_revisions>   <size_of_data>

                                            ... the name ..

       ^BI   <hostname>   <path>   <name>   <type>   <variant(unused)>

                                          ... and the owner ..

       ^BO   <owner's_name>   <owner's_host>   <owner's_domain>

                        ... followed by some attributes for the busy version ...

       ^BP   <gen_>   <rev_of_physical_predecessor>
       ^BL   <locker's_name>   <locker's_host>   <locker's_domain>   <date_of_last_lock_change>

                         ... and the revision list, that contains all standard
                                 attributes for non-busy versions. ...

       ^BR   <generation>   <revision>   <state>   <mode>   <variant(unused)>
            ^BA   <author's_name>   <_host>   <_domain>   <locker's_name>   <_host>   <_domain>
            ^BT   <date_of_last_modification>   <_last_access>   <_last_status_change>   ...
                                        ...   <_saving>   <_locking>
            ^BM   <kind_of_representation>   <size_of_file>   <size_of_delta>   ...
                      ...   <gen_>   <rev_of_phys._successor>   <gen_>   <rev_of_phys._predecessor>
       ^BR ...
       ^BR ...

                      ... Now follows the list of lists of user defined attributes
                 ("-2 -2" indicates the busy version; "@" stands for a null byte). ...

       ^BUSEG
       ^BU -2 -2
       machine=vax@data=fs@@
       ^BU   <gen>   <rev>
       name=value@@
       ^BU ...

       The structure of the datafile:

       Data are represented either by deltas or by complete data-chunks...

       ^BDATA   <archive_format_version>

       ^BN   <gen>   <rev>   <size_of_note>
       --- empty log message ---

       ^BD   <gen>   <rev>   <kind_of_representation>   <size_of_data>
       A typical delta looks like:
       @67723@@@@44@67756@^A14@some text@6635@ and so on.
       Deltas are indicated by a "1" at the "kind_of_representation" field.

       ^BN   <gen>   <rev>   <size_of_note>
       This is a log message

       ^BD   <gen>   <rev>   <kind_of_representation>   <size_of_data>
       A "0" at the "kind_of_representation" field indicates that this
       version is stored completely.

       ^BN ...

       ^BD ...

AUTHOR

       Andreas Lampen, Tech. Univ. Berlin (andy@cs.tu-berlin.de)