Question

22. What is the difference between multiprogramming and multiprocessing? 23. What do we mean by an entry section, a critical section and an exit section in a program? 24. What are deadlocks and how can a spin lock help to avoid deadlocks? 25. Be able to interpret a resource allocation graph: (a) Understand what constitutes a cycle and what it means (b) Be able to interpret a resource allocation graph (c) Identify deadlock conditions

Answer 1

22)difference between multiprogramming and multiprocessing:

Usually multiprogramming keeps some programs in main memory at the same time and executing using single CPU. While multiprocessing is the term od processing multiple processes at the same time using multiple cpu's.In Multi programming context switching takes place while multi processing permits parallel processing. Multiprogramming takes more time while multi processing takes less time.

23.
Entry section: In the entry section, usually process requests for inputs for critical section.
Critical section: It is nothing but the code segment which can be accessed by only one process at a time.
Exit section: Exit section is for giving output.

24. Deadlock:Deadlock is nothing but a situation where a process holding a resource and waiting for another resource acquired by some other process.
Soinlock:spinlock is a locking machanism which causes a thread while trying to get simply wait in a loop and repeatedly checking if the lock is available. So that by this locking macanism we can avoid deadlock