The latest Linux kernel supported is 2.4.19. Later versions of the 2.4 series will be supported, as will kernel versions in the 2.5 series.
You should use gcc-2.95.3 as this is the recommended compiler for 2.4 kernels. This is a Linux kernel requirement, not just an openMosix requirement. However, nothing precludes you from having, on the same system, gcc-2.95.3 for kernel compiles and gcc-3.x for non-kernel compiles.
Additional notes: There are many kernel-related issues with gcc-3.x compilers. Inlining, optimization and page alignment do strange things to operating systems kernels. The standard Linux kernel is only guaranteed to compile and work properly with gcc 2.95.3.
However, the Red Hat gcc 2.96 compiler is 2.95 + RH patches. In this case, you should ensure you use gcc-2.96-74 or later. gcc-2.96-54 will not build the kernel correctly. In addition, please pay attention to compiler optimization. Anything greater than -O2 may not be wise. Similarly, if you choose to use gcc-2.95.x or derivatives, be sure not to use -fstrict-aliasing (which, depending on your version of gcc 2.95.x, may necessitate using -fno-strict-aliasing).
Treat an openMosix kernel just like any other kernel. The openMosix system is simply an extension to the kernel, and will be treated like a standard kernel by your bootloader.
19.3.4. I installed a Linux distribution and it says that its kernel is x.x.x-x. The openMosix README says not to mix kernel versions. Does that mean that the openmosix-x.x.x-y RPM will not work on my machine?:
No. It means is that if you install openMosix on your cluster, all your machines should have the openmosix-x.x.x-y kernel installed. You should not mix kernels which have different kernel versions, i.e. do not mix openmosix-x.x.z-x, and openmosix-x.x.x-y, etc.