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 file allocation using i nodes, File allocation using I nodes. T...

File allocation using I nodes. This method is used to decrease the size of the table in the above method. Every file will have an I-node list. Allow a file have 15 pointers a

Give an overview of windows 2000 file management, Give an overview of WINDO...

Give an overview of WINDOWS 2000 file management. Windows makes use of the NTFS and File Allocation Table file systems. The Older versions of the FAT file system had file name

Explain process scheduling in time sharing, Explain process scheduling in t...

Explain process scheduling in time sharing The relevant features of time sharing are: 1.      Process priorities do not depend on the nature of the processes 2.      Proc

Define ageing, Define Ageing Ageing is a method of enhancing the priori...

Define Ageing Ageing is a method of enhancing the priority of process waiting in Queue for CPU allocation

List the task regions in the spiral model, List the task regions in the Spi...

List the task regions in the Spiral model.  Customer communication - In this region it is suggested to set up customer communication.  Planning - All planning activities

What is the use of FIFOs in client-server applications, What is the use of ...

What is the use of FIFOs in client-server applications

Utility programs, Utility Programs: those programs which are not the essen...

Utility Programs: those programs which are not the essential part of operating system. But they provide different utilities / features to the users e.g. MS-DOS : Fdisk, FORMAT, AT

Producer-consumer, The general idea of a producer-consumer architecture is ...

The general idea of a producer-consumer architecture is related to building a pipeline of threads, similar to the web spider from Project 2. Each step of the processing will now be

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