# @(#)README	1.6 20/09/04 Copyr 1997-2020 J. Schilling

Star is a tar like archiver - TAR stands for Tape ARchiver.


Star saves many files together into a single tape or disk archive,
and can restore individual files from the archive. It includes a FIFO
for speed, a pattern matcher, multivolume support, the ability to correctly 
archive sparse files, automatic archive format detection, automatic byte order
recognition, automatic archive compression/decompression, remote archives
and special features that allow star to be used for full backups. it includes
a built in find(1) command that allows one to execute find(1) expressions.
It also includes `rmt', a truly portable version of the remote tape server
that supports remote operation between different OS and machine architectures
(hides even Linux oddities) and a portable `mt' tape drive control program
that is able to use the remote tape interface.

The RMT program if 100% compatible with Sun's extensions for inter-platform
operability support (MT status codes) and with GNU extensions for inter-platform
open() interoperability. In addition, it includes my enhancements that
hide Linux MT-ioctl non compliances with other UNIX platforms.

Star is the fastest known implementation of a tar archiver.
Star is even at least 30% faster than ufsdump.

Star development started 1982, the first complete implementation has 
been done in 1985. I never did my backups with other tools than star.

Its main advantages over other tar implementations are:

	built-in find		- star is built on top of libfind and thus
				  allows you to execute "find" like expressions
				  in create, extract and list mode. This allows
				  to do a lot of interesting things that could
				  not be done if star and find would be called
				  separatedly

	fifo			- keeps the tape streaming.
				  This gives you at least 30% faster backups
				  than you can achieve with ufsdump or any
				  other known backup method.

	remote tape support	- a fast RMT implementation that has no
				  probems to saturate a 100 Mb/s network and
				  faster networks are usable depending on
				  the quality of the network implementation
				  and the speed of the filesystem.

	selectable cli		- star cli=xxx allows one to select a command
				  line interface from the list

					star, suntar, gnutar, pax, cpio.

	accurate sparse files	- star is able to reproduce holes in sparse
				  files accurately if the OS includes 
				  the needed support functions. This is
				  currently true for Solaris-2.3 to
				  Solaris-2.5.1 and for Solaris-10 or newer

	infinite path name length - star has no path name limitation at
				  all. It is even able to deal with
				  path names that are longer than the
				  OS limitation PATH_MAX, that is usually
				  1024 octetts.

				  Before July 2018, star did archive and
				  extract Pathnames up to 1024 Bytes. Since
				  July 2018, star deals with long names of
				  arbitrary length. The same limitation
				  applies to linknames. 

	pattern matcher		- for a convenient user interface
				  (see manual page for more details).
				  To archive/extract a subset of files.

	sophisticated diff	- user tailorable interface for comparing
				  tar archives against file trees
				  This is one of the most interesting parts
				  of the star implementation.

	no namelen limitation	- Pathnames up 8 GBytes may be archived.
				  (The same limitation applies to linknames)
				  This previous limit was 1024 Bytes (up to
				  June 2018).

	deals with all 3 times	- stores/restores all 3 times of a file
				  (even creation time)
				  With POSIX.1-2001 the times are in nanosecond
				  granularity.
				  Star may reset access time after doing
				  backup. On Solaris this can be done without
				  changing the ctime.

	deals with nanoseconds  - Timestamps are supported with nanosecond
				  granularity (depending on the archive type).

	does not clobber files	- more recent copies on disk will not be 
				  clobbered from tape
				  This may be the main advantage over other
				  tar implementations. This allows
				  automatically repairing of corruptions
				  after a crash & fsck (Check for differences
				  after doing this with the diff option).

	automatic byte swap	- star automatically detects swapped archives
				  and transparently reads them the right way

	automatic format detect	- star automatically detects several common
				  archive formats and adopts to them.
				  Supported archive types are:
				  Old tar, gnu tar, ansi tar, star,
				  POSIX.1-2001 PAX, Sun's Solaris tar, cpio.


	automatic compression detect - star automatically detects whether the
				  archive is compressed. If it has been
				  compressed with a compression program that
				  is compatible to decompression with "gzip"
				  "bzip2", "lzop" or "p7zip", star automatically
				  activates decompression.

	fully ansi compatible	- Star is fully ANSI/Posix 1003.1 compatible.
				  See README.otherbugs for a complete
				  description of bugs found in other tar
				  implementations. Star is the first tar
				  implementation that supports POSIX.1-2001.

	support for ACLs and file flags - star supports Access Control Lists
				  and extended file flags (as found on FreeBSD
				  and Linux). Support to archive and restore
				  other file properties may be easily added.

	support for all inode metadata - star supports to put all inode
				  metadata on the archive. This allows future
				  versions of star to perform true
				  incremental dumps.

	sophisticated error control - allows one to tell star which error types
				  should be ignored for wich file name pattern.
				  This allows one to write backup scripts that
				  give no error messages for all problems that
				  are tolerable (e.g. growing log files). 

	'ed' like pattern substitutuions - star supports automated pattern rule
				  based file name substitution as documented
				  for 'pax'. 

	fast built in -copy mode  - allows one to make fast and accurate copies
				  and directory tree comparisons. 

	True incremental dump/restore features - tar is the first TAR based
				  backup system that has been verified to
				  handle typical file system changes
				  correctly.

				  Star uses the same method as
				  ufsdump/ufsrestore but acts OS and FS
				  indeependent.

Have a look at the manual page, it is included in the distribution.


Author:

Jörg Schilling and the schilytools project authors.

Please report issues to schilytools@mlists.in-berlin.de or open a
ticket at https://codeberg.org/schilytools/schilytools.
