Traditionally, GNUish archives are made using Rahul Dhesi's zoo
archiver. This archive format is popular and portable, used in many
places, notably for the Usenet `comp.binaries.ibm.pc' exchange
group. The GNUish project selected it because it works on OS/2, DOS,
and UNIX, and all the sources are freely available. Moreover, it offers
a nice user interface and is dependable.
Some people wanted GNUish to use zip for its better compression,
but zip was proprietary software at that time. A new version of
zoo (version 2.1) offers a higher compression rate, comparable to
what zip can achieve. About at the same time, the
Info-ZIP
group produced a zip program available in source
form, and which works on OS/2, DOS, and UNIX. There are no more big
reasons for using one instead of another.
Also, some sites converted all of GNUish to ARC or LHarc
format. Instead of feeding an archivers war, let us simply hope that
each archive site will follow the GNU spirit and at least offer the free
archiver they use, both in executable and complete source form.
The current maintainer has been urged by several of the major sites to use zip for all files in the collection, and to keep archive names in the "8+3" lower-case format (filenames within a zip archive are not subject to such restrictions). Some files remain in other formats, but eventually all will be converted.
Most packages consists of two archives, one for the complete source and documentation, the other for the executable and data files; however, it happens that the documentation is sometimes provided with the executables. The filename for a package archive is often selected according to the following pattern:
program version edition sequence.extension
In this syntax, program is a short string to identify the product,
e.g. `futi' indicates GNU file utilities; while version is a
decimal integer naming the version, without any decimal point, v.g.
`14' for 1.4, `358' for 3.58; edition is `a' for
the first release in GNUish, then `b', `c', etc., for
subsequent editions. The value of sequence is the letter `s'
for the source and documentation, or `x' for executable and data
files. When extension is `zoo', this usually refers to Zoo
version 2.1. The `tgz' extension is shorthand for `tar.gz',
and both gzip (see section gzip) and tar (see section tar) will be
required to "un-tgz."