IPC's indirect message forwarding may use process address space mailboxes (or in the kernel). Process address space is shared-memory region. Indirect message forwarding and shared memory use process address space, so what's the difference?

Consider the following statements about user level threads and kernel level threads. Which one of the following statement is FALSE? (A) Context switch time is longer for kernel level threads than for user level threads. (B) User level threads do not need any hardware support. (C) Related kernel level threads can be scheduled on different processors in a multi-processor system. (D) Blocking one kernel level thread blocks all related threads.

hat is a virtual address and how is it converted into an actual address?

When a process is in the "Blocked" state, waiting for an I/O operation to complete. When a service is canceled, it enters one of the following states: a) State of Termination, b) State of Suspension, c) State of Running, or d) State of Readiness.