rtbuf.c is an implementation of a buffering scheme using the POSIX realtime

features. Its aim is to provide smooth playback of MPEG audio streams

even on a very heavily loaded machine. It uses many advanced features

of the operating system:

- System V shared memory

- POSIX.1b realtime scheduling extensions

- POSIX.1b memory locking

- Sound Driver DMA buffer mapping into the user proces space

Make sure that you have enabled these features! The downside

of these features is that they can only be used if the process has

root permissions. Using realtime features is somewhat dangerous, since

a realtime process can eat all the CPU time, rendering the machine

unresponsive. So don t try this on your server!