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

What is the sequence in which resources may be utilized, What is the sequen...

What is the sequence in which resources may be utilized? Under normal mode of operation, a process may utilize a resource in the following sequence: Request: If the requ

In which page replacement policy balady’s anomaly occurs, In which page rep...

In which page replacement policy Balady’s anomaly occurs? FIFO (First in First Out)

Is disk scheduling except fcfs scheduling, Q. Is disk scheduling except FC...

Q. Is disk scheduling except FCFS scheduling useful in a single-user environment? describe your answer. Answer: In a single-user environment the I/O queue typically is empty.

Aggregate planning, Prepare a report that motivates alternatives reactive s...

Prepare a report that motivates alternatives reactive strategies that can be used by wind Mud clothing factory

Explain the real time operating system, Explain the Real Time Operating Sys...

Explain the Real Time Operating System A real-time operating system comprises definite, fixed time constraints. Processing should be done in the defined constraints, or the sys

What are the three major purposes of an operating system, Q. What are the t...

Q. What are the three major purposes of an operating system? Answer: To offers an environment for a computer user to execute programs on computer hardware in a conveni

Microsoft, Discuss the high barriers to entry in the market for PL operatin...

Discuss the high barriers to entry in the market for PL operating systems

Define swapping, Define swapping. A process requires being in memory to...

Define swapping. A process requires being in memory to be executed. Though a process can be swapped temporarily out of memory to a backing store and then brought back into memo

Timers could be utilized to compute the current time, Q. Timers could be ut...

Q. Timers could be utilized to compute the current time. Provide a little description of how this could be accomplished. Answer: A program could utilize the following ap

Cpu scheduling alogarithm program in javascript, a program that can do cpu ...

a program that can do cpu scheduling algorithm priority using javascript or php to display gaant chart and calculate waiting and average waiting time

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