What is hard disk and what is its purpose?

Correct Answer: Hardware device that maps virtual to physical address In MMU scheme, the value in the relocation register is added to every address generated by a user process at the time it is sent to memory ->The user program deals with logical addresses; it never sees the real physical addresses

Correct Answer: A hard real-time system guarantees that critical tasks complete on time This goal requires that all delays in the system be bounded from the retrieval of the stored data to the time that it takes the operating system to finish any request made of it A soft real time system where a critical real-time task gets priority over other tasks and retains that priority until it completes As in hard real time systems kernel delays need to be bounded

Correct Answer: Micro-kernal : A micro-kernel is a minimal operating system that performs only the essential functions of an operating system All other operating system functions are performed by system processes Monolithic : A monolithic operating system is one where all operating system code is in a single executable image and all operating system code runs in system mode

Correct Answer: When a process requests an available resource, system must decide if immediate allocation leaves the system in a safe state System is in safe state if there exists a safe sequence of all processes Deadlock Avoidance : ensure that a system will never enter an unsafe state

Correct Answer: Mutual exclusion Hold and wait No preemption Circular wait

Correct Answer: Dispatcher module gives control of the CPU to the process selected by the short-term scheduler; this involves: Switching context, Switching to user mode, Jumping to the proper location in the user program to restart that program, dispatch latency ââ?¬â?? time it takes for the dispatcher to stop one process and start another running

Correct Answer: 1 Mutual exclusion (where at least one resource is non-sharable) 2 Hold and wait (where a process holds one resource and waits for other resource) 3 No preemption (where the resources can?t be preempted) 4 Circular wait (where p[i] is waiting for p[j] to release a resource i= 1,2,?n j=if (i!=n) then i+1 else 1 )

Correct Answer: An interpreter reads one instruction at a time and carries out the actions implied by that instruction It does not perform any translation But a compiler translates the entire instructions

Correct Answer: Distributed systems work in a network They can share the network resources, communicate with each other

Correct Answer: Mutex is the short form for ?Mutual Exclusion object? A mutex allows multiple threads for sharing the same resource The resource can be file A mutex with a unique name is created at the time of starting a program A mutex must be locked from other threads, when any thread that needs the resource When the data is no longer used / needed, the mutex is set to unlock