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

Write a short note on peer-to-peer computing, Write a short note on peer-to...

Write a short note on peer-to-peer computing. Peer-to-peer (P2P) system model is a kind of distributed OS. In this model, clients and servers aren't distinguished from one anot

Explain kernel-level threads (klt), KERNEL-LEVEL THREADS (KLT) In this...

KERNEL-LEVEL THREADS (KLT) In this level every thread management is done by kernel .No thread library except an API system calls to the kernel thread facility exists. The kern

Explain the scheduleworktodo function used in netware, Explain the Schedule...

Explain the ScheduleWorkToDo Function used in Netware ScheduleWorkToDo(MyThread Function, arg, workToDo) The ScheduleWorkToDo ( ) function is specific to NetWare 4.0. This c

What are the different files attributes?, What are the different files attr...

What are the different files attributes? File name:-it's the name of the file. It's the name with which the user identifies. Identifiers:-it's created when a file is created

What are the steps followed in testing, What are the steps followed in test...

What are the steps followed in testing? i. Unit testing - The individual components are tested in this type of testing. ii. Module testing - Related collection of independen

Explain lru additional reference bits algorithm, Additional Reference bits...

Additional Reference bits algorithm Here we keep an 8-bit byte for every page in memory. At standard intervals the reference bit is shifted by the OS. If a shift register conta

NETWORK OPERATING SYSTEM, explain about design issues of network operating ...

explain about design issues of network operating system

Explain the concept of reentrancy, Explain the concept of Reentrancy? I...

Explain the concept of Reentrancy? It is a useful, memory-saving method for multiprogrammed timesharing systems. A Reentrant Procedure is one in which many users can share a si

Memory management, 4. Describe priority scheduling algorithm. Consider the ...

4. Describe priority scheduling algorithm. Consider the following set of processes. Show the order in which the algorithm will schedule these processes. Assume preemptive and non-p

Describe virtual memory, What is virtual memory? Virtual memory is a me...

What is virtual memory? Virtual memory is a method that allows the execution of processes that might not be completely in memory. It is the separation of user logical memory fr

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