Re: Difference between tar and ar

Greetings.

In article <slrne2eed7.1jtf.random832@xxxxxxxxxxxxx>, Jordan Abel wrote:
Tar headers are large. Each header fills a 512-byte sector.
Files' contents are also padded, so that each files' header is
always aligned with the start of a tape sector. The headers
also contain checksums, so that it's possible to salvage some
files from a damaged tape.

Unless you do something moronic like compress the whole archive as one
big lump of data. But no-one would ever do that, right? Heh, almost my
whole reply, composed before i read the above paragraph, was a lengthy
description of the tar format, including an illustrated dump of a tar
file containing the same two files as the ar file above. Seems kind of
empty now that i've deleted it.

Seriously, someone should build a compress-each-file extension on top of
the tar format.

I think that would be vastly less efficient than simply producing some
error-correcting redundancy data for the file. Free utilities for
producing such data are already available; a simple shell script wrapper
around tar could easily serve as the "extension" you propose. It has the
further benefit that the redundancy data can be stored separately from the
tarball.

Regards,
Tristan

--
_
_V.-o Tristan Miller [en,(fr,de,ia)] >< Space is limited
/ |`-' -=-=-=-=-=-=-=-=-=-=-=-=-=-=-= <> In a haiku, so it's hard
(7_\\ http://www.nothingisreal.com/ >< To finish what you
.