can we modify the int 0x80 routine

Question

1. how does linux 2.6 differ from 2.4?
2. can we modify the source kernel ?
3. can we modify the int 0x80 service routine?

Answer 1

1. It's an architectural overhaul. Everything has changed internally. SMP support is complete, the process scheduler is vastly improved, memory management got an overhaul, and many, many other things.
2. Yes. It's open-source software. If you do not have a copy of the source, you can get it from your vendor or from kernel.org.
3. Yes, but it's not advisable because it will break libc, it will break your baselayout, and it will break your toolchain if you change the sequence of existing syscalls, and nearly everything you might think you want to do should be done in userspace when at all possible.