Source: snapvoip.blogspot.com

If you are wondering what is ASTLinux, You will have to visit ASTLinux site. I will try my best to describe it in a few sentences.
AstLinux is a custom Linux distribution centered around Asterisk, the Open Source PBX. Although Asterisk remains the core focus, other VoIP applications such as OpenSER are also available. AstLinux has many features that make it ideal for embedded and commercial Asterisk based solutions. However, it can be easily configured to adapt to nearly any situation.
AstLinux has been designed with running from Compact Flash memory in mind. However, it can also be installed to a regular hard drive like other distributions. AstLinux currently occupies around 40mb of disk space, so any Compact Flash card (or hard drive) of 64mb or larger will work perfectly.

AstLinux is also the premier Asterisk Live CD. The AstLinux ISO image is very small, yet it includes two AstLinux versions (net4801 and i586), Windows AutoRun support, and of course, el-torrito booting. Try the best asterisk linux distribution today!

ASTLinux documentation is also updated and available from VOIP-INFO.ORG Check out the links. The distribution itself available from Sourceforge, the new home of ASTLinux.
What’s in 0.4.4?
Changes:
- include rhino support
- include misdn support
- include arno’s firewall by default
- update net4801/wrap kernel config to include USB ethernet adapters
- update Asterisk/Zaptel versions (1.2.12.1/1.2.9.1)
- major build system improvements
- include openssl binary in build

Links;
ASTLinux Home
ASTLinux at Sourceforge
ASTLinux documentation at VOIP-INFO.ORG