Hints for using extended POSIX.1-2001 headers: Star will understand extended headers if the archive format is from 'star', 'ustar', 'pax', 'xustar', 'exustar'. In addition, star will understand the POSIX-look-alike extended headers from Sun's tar (Solaris) if 'suntar' is selected or autodetected. Star will create extended POSIX headers when the archive format is 'pax', 'xustar' or 'exustar'. When the archive format is 'exustar', every file will get an extended header which holds at least atime/ctime/mtime in sub-second resolution. If the archive format is 'pax' or 'xustar', star will create the extended header only if there is a need for the extended header because one or more of the fields do not fit into the standard ustar header. Star supports the following fields in the extended header: times: "atime" "ctime" "mtime" (create/extract) id's (numeric): "uid", "gid" (create/extract) id's (names): "uname", "gname" (extract only) pathnames: "path" "linkpath" (create/extract) filesize: "size" (create/extract) Additional: "charset", "comment" (extract only - ignored) Vendor unique: "SCHILY.devmajor" "SCHILY.devminor" (create/extract) In -dump mode (a preparation for incremental dumps) star archives: "SCHILY.dev" The field stat.st_dev - the filesys indicator "SCHILY.ino" The field stat.st_ino - the file ID # "SCHILY.nlink" The field stat.st_nlink - the hard link count "SCHILY.filetype" The real file type - this allows e.g. socket/door These fields will in future allow star to archive and extract all information that is needed for incremental dumps. Star now includes ALL file metadata that is available. This allows a complete restauration of all file properties and a diff mode that checks for diffs in all file properties. Sun compatibility: "SUN.devmajor" "SUN.devminor" (extract only) With -Hsuntar: "SUN.devmajor" "SUN.devminor" (create/extract) TODO List for extended headers: - Add better UNICODE support - Add some way of handling UID/GID Overflow in the traditional 7 char fields which limit to 2097151. - Add support for sparse files and continuation Files into the extended header stuff (as Vendor UNIQUE extensions with 'SCHILY.*' name). How to use extended POSIX.1-2001 headers: - To emmit xhdr's only if really needed, use 'star -Hpax' or 'star -Hxustar'. In this case extended headers will be created if the path/linkname will not fit into the 'ustar' header or if the filesize is > 8 GB or uid/gid will not fit 07777777. - To emmit xhdr's always, use 'star -Hexustar' and even when no other extended attribute is needed atime/mtime/ctime are written in sub-second resolution. - To write extended headers simuilar to POSIX.1-2001 as used by the Solaris tar, use 'star -Hsuntar' and every file will at least get a sub-second reaolution mtime. Note that Sun's main intention was to handle very long filenames and big uid/gid's.