Important features of the 2.4 process scheduler

I am reading the book process scheduling chapter from the "Understanding the Linux kernel" book. Following are some of the important points about the 2.4 kernel scheduler.

1) Process scheduling in Linux is Time Shared.
2) Processes are preemptive in the 2.4 Linux kernel.
3) The need_resched flag is set whenever the time quantum assigned to the process expires.
4) The 2.4 kernel is non-preemptive i.e. a process can be preempted only when it is executing in the User mode and canNOT be preempted when the process is running in the kernel mode.