Non Determinism in Operating Systems

I<>Operating and Real Time systems are non-deterministic, in that they must respond to events that occur in an unpredictable order, and at unpredictable times. Such as results generated from I/O devices.

• The way an Operating system switches between processes cannot be pre-determined, since the events which cause the switches are not deterministic.
• The interleaving of instructions, executed by a processor, from a set of processes is non-deterministic

The Events or Interrupts cause process switches, such as an I/O completion interrupt causing the OS to switch to an I/O handling process.