| Question: | |
|---|
| ______ & _____ are atomic operations in almost all systems | |
| These mechanisms ensure that only one process is doing certain things at once (others are excluded)- most of these include a locking mechanism | |
| What are the correctness criteria for P/V bounded-buffer problem? | |
| This is an integer variable that can be accessed only through two atomic operations, P() and V(). (invented by Dijkstra) | |
| What are the three elements of locking? | |
| This is an atomic operation that increments the semaphore S by 1 | |
| after ______, control returns back to next instruction in the program (ret. address- the PC at that point- is pushed onto stack) | |
| This consists of a lock and zero or more condition variables for managing concurrent access to shared data | |
| Type of semaphore whose integer variable can range over an unrestricted domain | |
| this is a semaphore that is restricted to locked/unlocked, 0/1, available/unavailable, etc. | |
| Disadvantages of using Process (2): | |
| What do you call performing activities one after another? | |
| The two methods for the birth of a process: | |
| Interrupts are _____ while the first interrupt is being processed | |
| What are the 3 classic problems of synchronization? | |
| This is an atomic operation that waits for a semaphore to become positive, then decrements it by 1 | |
| ______ is when the OS saves the state (PC, PSW, regs) of a process and then restores the state of another process (ie. a process that is in the ready state) | |
| When should an OS perform context switching? | |
| variables shared between multiple processes are called | |
| main advantage of multiprogramming? | |
| As a resource manager, what are the OS's main concerns? | |
| what is a process? | |
| This is the basic unit of CPU utilization; has PC, regs, stack; same address space, open files, signal handlers as process | |
| Components of a program, called sectors: (4) | |
| For every interrupt, there's a fixed mem location for ______ | |
| This is when the user decides which threads map to distinct kernel threads and which share | |
| Three operations on condition variables: | |
| In this mode, the executing code has complete and unrestricted access to the underlying hardware. It can execute any CPU instruction and reference any memory address | |
| When you map user-level threads to kernel threads, this is of the _______ model | |
