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

List ways to share directories in operating system, List ways to share file...

List ways to share files among directories in operating systems. a. Copy file from one account into another. b. Link directory entry of "copied" file to directory entry of o

Explain lru enhanced second chance algorithm, Enhanced Second chance algori...

Enhanced Second chance algorithm In this a modify bit is as well used. Now if the ordered pair of reference and modify is (0,0) neither recently used nor modified - the best

Explain segmentation hardware?, Explain segmentation hardware? We defin...

Explain segmentation hardware? We define an completion to map two-dimensional user-defined addresses into one-dimensional physical addresses. This mapping is affected by means

Thread pools, Another solution then would be to keep a pool of threads. Whe...

Another solution then would be to keep a pool of threads. Whenever a new task arrives, the system would simply get a thread from pool and set that thread to work on the given task.

Explain the general structure of a typical process, Explain the general str...

Explain the general structure of a typical process? There are basically four main sections through which each of the process has to pass through.The universal algorithm is:-

Protection, Can you please explain in easy words how input output protectio...

Can you please explain in easy words how input output protection works

What are the operations of a directory, Operations that are to be performed...

Operations that are to be performed on a directory are Search for a file: We are able to find all files whose names match a exact pattern. Create a file: New files requi

Explain the types of system calls, Explain the Types of System Calls Th...

Explain the Types of System Calls The major types of system calls are like this: a. Process Control: These types of system calls are employed to control the processes.

Inventory differences, What makes a Just-in-Time inventory system differ fr...

What makes a Just-in-Time inventory system differ from a traditional inventory system?

What are the operations of processes, What are the operations of processes?...

What are the operations of processes? Process creation A process may create several new processes. The creating process is called as parent process, where as the new proce

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