Reference counting, Operating System

Assignment Help:

The idea of reference counting is to maintain, for every object, the total number of references to that object, i.e. the number of "incoming" pointers. Whenever the number of references is zero we know that the object is not accessible through any pointers, and thus it is garbage. Also, whenever we choose to delete some useless object,we have to recursively check that object to see if it contains pointers to other objects; if so, we have decrement the reference counters for those objects as well. One problem of reference counting, though, is how to deal with cycles. Suppose object A points to B, and B points to A. If these objects can only be reached through each other, we have to free them too, even though their counters are not zero! Note that cycles can common inmany data structures; for example, consider a doubly-linked list. The commonly adopted solution to this problem is to run mark-sweep now and then, in order to remove cyclic references, and then run normal reference counting on the rest of the time.


Related Discussions:- Reference counting

Explain rehashing to handle collision, Explain Rehashing to Handle Collisio...

Explain Rehashing to Handle Collision Rehashing:  Re-hashing schemes make use of a second hashing operation while there is a collision. If there is an additional collision, we

Define page stealing, Define Page stealing    Page stealing is taking ...

Define Page stealing    Page stealing is taking page frames another working sets

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

Define drawback of distributed systems, Define drawback of Distributed syst...

Define drawback of Distributed systems Reliability is a drawback of Distributed systems

Write note on process, Write note on process, process state? A process ...

Write note on process, process state? A process is in excess of the program code which is sometimes known as text section. It as well includes the current activity as represent

Explain the protection problems, Q. In some systems a subdirectory is able...

Q. In some systems a subdirectory is able to be read and written by an authorized user just as ordinary files can be. a. Explain the protection problems that could arise. b.

Software for business management integrated into network, Software for busi...

Software for business management integrated into a social network Project Description: We are seeking top professionals to build software with us that manages the business.

Explain hierarchical paging, Hierarchical paging Single way is to use a...

Hierarchical paging Single way is to use a two-level paging algorithm, in which the page table itself is also paged. A logical address is separated into a page number and a pag

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