User's Manual

8 Chapter 1. What is TUX?

1.1. New TUX 2.1 Features

The TUX 2.1 release is an incremental upgrade to TUX 1.0 and keeps source-code level com-

patibility with user-space modules.

The incremental enhancements include

• True zero-copy disk reads — Whereas TUX 1.0 copied ﬁles into a temporary buffer, TUX

2.1 is integrated with the page cache and thus uses zero-copy block IO.

• Generic zero-copy network writes — TUX 2.1 uses the generic zero-copy TCP framework.

• Zero-copy parsing — Where possible, TUX parses input packets directly. Even in RAM-

limited situations, TUX now does full, back-to-back zero-copy I/O.

Other changes include

• Enhanced user-space utilities and module support.

• Mass virtual hosting support — The host-based virtual server patch has been added to

TUX. There is no limit on the number of virtual hosts supported, only RAM and diskspace.

• CGIs can be bound to particular CPUs or can be left unbound.

• A number of bugs were ﬁxed which caused performance problems — TUX 2.1 is now

signiﬁcantly faster than TUX 1.0!

1.2. Summary of System Requirements

• TUX Customized 2.4.x-based version of the kernel or higher

• x86, Alpha, IA64 or PowerPC/64 platform (should work on PowerPC/32, untested on

Sparc)

• Alternate web server such as Apache running on the same server to process unknown

requests

1.2.1. Current Limitations

• TUX can only call the other Web server such as Apache on the same server. In future

revisions, it will allow the rollover of unsupported content to an alternate server.