Could any one please help me in understanding the difference between pax,tar and cpio. all of them basically creates archive files.
cpio is more advanced than tar, in a way that it can preserve file ownership, permissions and even timestamps. But it is also not so easy to use. I don't know much about pax. From what I remember it can convert between some archive formats or something 
Hi.
See http://en.wikipedia.org/wiki/List\_of\_archive_formats
Google, Wikipedia and man pages are your friends for factual information ... cheers, drl
cpio has many limitations and so does tar.
"tar" hopefully does that too.
The cpio utility is depreciated circa POSIX 2001 because it can't hold files >8GB.
So does any sensible UNIX archiver. tar does this by default. It was kept and extended to allow >8GB files while keeping backwards compatibiltiy with old tar: files < 8GB still use octal fields, but files >8GB use binary fields in such a way that archivers who don't understand those fields will ignore them.
The new pax format is in fact an extension of this extended tar, with a huge default blocksize and one optional extra field to carry filenames, group ID's, etc. that can't fit inside a normal tar's fields(groupid's > 07777777, etc.)
Sorry guys, little brain freeze or something, I mixed "tar" with "cp" 
Standard "cpio", "tar" and "pax" have a 2Gb maximum size of any one file. There may be enhanced versions but don't assume cross-platform compatibility.
standard "tar" has a much bigger limit now, but old versions persist in many places.
Of course PAX supports large files. It's not a modern restandardization of something old, it's a brand-new archiver invented by IEEE&POSIX and decreed by POSIX to support all the modern extensions for tar as well as it's own pax format. I suspect because they'd have to pry some distributor's mouldy old tar implementations from their cold dead fingers to get USTAR implemented anywhere else.
Of course, it being an actually portable archiver, nobody installs it 
Hi.
I just noticed that one of the archivers available in GNU/Linux Debian (lenny) is:
Description: tar(1) from FreeBSD, using libarchive
The bsdtar program has a number of advantages over previous tar
implementations:
.
* Library. Since the core functionality is in a library, it can be
used by other tools, such as pkg_add.
.
* Automatic format detection. Libarchive automatically detects the
compression (none/gzip/bzip2) and format (old tar, ustar, gnutar,
pax, cpio, iso9660, zip) when reading archives. It does this for
any data source.
.
* Pax Interchange Format Support. This is a POSIX/SUSv3 extension to
the old "ustar" tar format that adds arbitrary extended attributes
to each entry. Does everything that GNU tar format does, only
better.
.
* Handles file flags, ACLs, arbitrary pathnames, etc. Pax interchange
format supports key/value attributes using an easily-extensible
technique. Arbitrary pathnames, group names, user names, file sizes
are part of the POSIX standard; libarchive extends this with
support for file flags, ACLs, and arbitrary device numbers.
Looks like a super-set of even PAX. Nothing is mentioned explicitly about sizes handled, and I have been able to get by with GNUtar, so I have no direct experience with bsdtar ... cheers, drl
tar is the best choice as it works well for the purpose. The cpio has some advantages when compared to tar , but it is quite complicated to control the use. The pax is not interesting one for me though it implements least privilege protections for memory pages and i have well experience with tar. One of the essay writing service attempt based on this items cleared some benefits of tar that actually works greatly for me. The selection also depends on several tasks that each one needs to accomplish.