PSAS/ RealTimeLinux

Early plans for LV2 called for the use of a hard RealTime operating system such as RTLinux. At this point it's not clear whether hard real-time is a requirement for the first launches of LV2.

Some useful references on Linux and RTLinux

Introduction to Real Time:
Linux Documentation Project:
Linux Kernel 2.4 Internals:
Linux Kernel Module Programming Guide:

A comparison of hard real-time Linux alternatives (22 Dec 2004):

RTLinux documentation:

RTLinux review at

Most of the documentation I see linked from seems to be quite old. I'd stick with the link above. Also, there are HTML versions of the official Getting Started and Installation guides in the RTLinux tarball.

RTLinux Setup Notes

RTLinux 3.1-pre3 (

) does


like Linux 2.4.7. Period. Sure, you could make it work, if you felt like adding back a pair of structure members that were globally removed from the kernel sometime after 2.4.5 (or re-coding critical parts of RTLinux). I'll pass on that.

The patch to 2.4.4 from RTLinux 3.1-pre3 does work on Linux 2.4.5. (I dunno whether this is a win.) The -N flag to patch causes it to ignore most of the things it would otherwise complain about, and though it produces a couple of prompts still, you can safely hit enter for those. There didn't seem to be any significant warnings when compiling either the kernel or the RTLinux modules.

The RTLinux example program "hello" runs successfully on my testbed Pentium 200 with 32Mb RAM. Currently this machine has 390Mb of disk space used - hey, little more than an order of magnitude away from our target! (Don't worry, that's mostly source code and compilers and the C library. Wait - we want libc. Darn.) Sadly I see no other example programs which do much of anything interesting, or I'd try things a little more thoroughly.

-- ?JameySharp - 01 Aug 2001