Mark-sweep, Operating System

Assignment Help:

The objects that a program can access directly are those objects which are referenced by local vari-ables on the processor stack, or by any global/static variables that refer to objects, or by variables in CPU registers. In the context of garbage collection, these variables are called the roots. An object is indirectly accessible if it is referenced by a ?eld in some other (directly or indirectly) accessible object. An accessible object is said to be live. Conversely, an object which is not live is garbage.

Note that heap objects which are live are indirectly accessible from the roots or other heap objects. The idea of mark-sweep is relatively straightforward. We start at the roots, and recursively visit every object accessible through pointers, marking them as live. At the end of the process, every thing not marked is considered garbage and will be deleted. Notice that mark-sweep can perform lazy garbage collection, in the sense that it does not necessarily need to remove the garbage immediately.

Note thatmark-sweep does not clean upmemory which is allocated, but simply never used. Also, periodically we have to visit all objects recursively, starting from the roots. For a large program, this will be slow. This is a problem with the traditional mark-sweep algorithm.


Related Discussions:- Mark-sweep

Explain why sstf scheduling tends to favor middle cylinders, Explain why SS...

Explain why SSTF scheduling tends to favor middle cylinders over the innermost and outermost cylinders. The center of the disk is the location having the fewest average distanc

Cpu scheduling algorithm, Q. A CPU scheduling algorithm determined an orde...

Q. A CPU scheduling algorithm determined an order for the execution of its scheduled processes. Convinced n processes to be scheduled on one processor how numerous possible differ

Define the term operating system, Question: a) Define the term ‘Operat...

Question: a) Define the term ‘Operating System' and identify two goals of an operating system. b) What do you understand by Symmetric multiprocessing (SMP) and Asymmetr

Implement a network-transparent system, Q. What are two dreadful problems t...

Q. What are two dreadful problems that designers should solve to implement a network-transparent system? Answer: One such issue is making all the processors as well as storag

Copy on write in virtual memory, how copy on write on pages when many proc...

how copy on write on pages when many process works at a same time?

Deadlock involving only one single process, Is it probable to have a deadlo...

Is it probable to have a deadlock involving only one single process? Describe your answer. Answer: No This pursue directly from the hold-and-wait condition.

Batch oriented and interactive operating system., properies of Batch orient...

properies of Batch oriented and interactive operating system.

Multiprogramming, what are the main advantages of multiprogramming

what are the main advantages of multiprogramming

Define process swapping , Swapping : Whole process is moved from the swap...

Swapping : Whole process is moved from the swap machine to the main memory for execution. Process size must be equal or less than to the used main memory. It is easier to exe

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd