Format of archive files in the attribute filesystem
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
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 [email protected][email protected]@ ^BU <gen> <rev> [email protected]@ ^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: @[email protected]@@@[email protected]@^[email protected] [email protected]@ 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 ...
Andreas Lampen, Tech. Univ. Berlin ([email protected])