What is CTAN?

The acronym stands for “Comprehensive TeX Archive Network”, which more-or-less specifies what it’s for:

• The archives offer a comprehensive collection of TeX resources.
• The content is made publicly accessible, via the internet.
• CTAN is a network of archives, which strive to stay in step with one another.

The basic framework was developed by a TUG working group set up to resolve the (then existing) requirement for users to know on which archive site a particular package might be found.

Actual implementation offers three distinct types of host:

• Core: Perform management functions as well as serving files to mirrors
• Mirrors: Take regular copies of core archives, and serve them to users
• Selector: A meta-service, which routes requests to an apparently “local” mirror (“local” is determined by an algorithm that uses your net address to determine where you are, and then selects a mirror that’s close)

Note that there is nothing to prevent any archive from supporting other functions, so a CTAN mirror may also operate as a CPAN (Perl) mirror and as a SourceForge (general free software) mirror, and …

Functions carried out by the core archive are:

• Uploads: users may submit new (or updated) material
• Notifications: Significant changes to the archive are reported via the mailing list ctan-ann@dante.de
• Catalogue maintenance
• Mirror monitoring

Users may make direct contact with the CTAN management team.

Users should ordinarily download material from CTAN via the archive selector: this uses the mirror monitor’s database, and uses the caller’s geographical location to offer an efficient choice of “sufficiently up-to-date” mirror site for you to connect to. This procedure has the advantage of distributing the load on CTAN mirrors.

FAQ ID: Q-ctan
Last updated: 2018-05-27