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

Essential properties of operating system, Essential Properties of Operating...

Essential Properties of Operating System 1. Batch: Jobs with similar needs are batched together and run through the computer as a group by an operator or automatic job sequen

Define the properties of interactive operating system, Define the propertie...

Define the properties of Interactive operating system Interactive:- This system is composed of many short transactions where the results of the next transaction may be unpred

Os structures, #question.explain varios types of system calls..

#question.explain varios types of system calls..

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

Taxation problem, Smith, who is a civil engineer, purchased a 30-hectare bl...

Smith, who is a civil engineer, purchased a 30-hectare block of land in Australia in 1986 and used two hectares of it as a main residence. The part that was not main residence cost

Explain the proper distribution of functionality and code, Explain the Prop...

Explain the Proper Distribution of Functionality and Code It is important to note that the bandwidth of the server operating system and server processor availability is fixed.

What is a general graph, What is a general graph? A tree structure wher...

What is a general graph? A tree structure where links can go from one branch to a node earlier in the similar branch or other branch, allowing cycles.

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.

Design issues of network operating system, expalin about the design issues ...

expalin about the design issues of network operating system

Describes responsibilities of the I/O manager, Q. Describes responsibilitie...

Q. Describes responsibilities of the I/O manager? Answer: The I/O manager is responsible for file systems and device drivers and network drivers. The I/O manager keeps follow

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