Operating System Interview Questions and Answers Part-4
The process of packaging and sending interface method parameters across thread or process boundaries.
32. What is a daemon?
Daemon is a program that runs in the background without users interaction. A daemon runs in a multitasking operating system like UNIX. A daemon is initiated and controlled by special programs known as processes.
33. What is pre-emptive and non-preemptive scheduling?
Preemptive scheduling: The preemptive scheduling is prioritized. The highest priority process should always be the process that is currently utilized.
Non-Preemptive scheduling: When a process enters the state of running, the state of that process is not deleted from the scheduler until it finishes its service time.
34. What is busy waiting?
The repeated execution of a loop of code while waiting for an event to occur is called busy-waiting. The CPU is not engaged in any real productive activity during this period, and the process does not progress toward completion.
35. What is page cannibalizing?
Page swapping or page replacements are called page cannibalizing.
36. What is SMP?
To achieve maximum efficiency and reliability a mode of operation known as symmetric multiprocessing is used. In essence, with SMP any process or threads can be assigned to any processor.
37. What is process migration?
It is the transfer of sufficient amount of the state of process from one machine to the target machine.
38. Difference between Primary storage and secondary storage?
Primary memory is the main memory (Hard disk, RAM) where the operating system resides.
Secondary memory can be external devices like CD, floppy magnetic discs etc. secondary storage cannot be directly accessed by the CPU and is also external memory storage.
39. Define compactions.
Compaction is a process in which the free space is collected in a large memory chunk to make some space available for processes.
40. What are residence monitors?
Early operating systems were called residence monitors.