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

Quick, why we say " OS is a resource allocator" and “OS is a control progr...

why we say " OS is a resource allocator" and “OS is a control program"?

Illustrate scope of consumer behaviour, Q. Illustrate Scope of Consumer beh...

Q. Illustrate Scope of Consumer behaviour ? Scope of consumer behaviour is extremely wide due to following reasons: >>Ever rising intensifying competition. >>Additional a

What are the main challenges for mobile computing, Question: (a) What ...

Question: (a) What are the main challenges for Mobile Computing? (b) What is the ISM band and what is particular about this frequency band? Name two wireless technologies

What is banker''s algorithm, What is banker's algorithm? Banker's algor...

What is banker's algorithm? Banker's algorithm is a deadlock avoidance algorithm that is applicable to a resource-allocation system with multiple examples of each resource type

Deadlock, what are the overall concepts of deadlock

what are the overall concepts of deadlock

Explain about disk scheduling with neat diagram, Explain about disk schedul...

Explain about disk scheduling with neat diagram? FCFS Scheduling SCAN scheduling C-SCAN scheduling SSTF scheduling LOOK Scheduling

What are the advantages and disadvantages of multithreading, What are the a...

What are the advantages and disadvantages of multithreading?  Advantages : Since by multithreading multiple executions are carried out in the same process environment t

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

What do you understand by “line balancing”? What happens if , What do you u...

What do you understand by “line balancing”? What happens if balance doesn’t exist?

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