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

Cpu, what is cpu

what is cpu

Evolution of operating system, breifly write a note on about evolution of o...

breifly write a note on about evolution of operating system?

Explain deadlock avoidance, Deadlock Avoidance It's a method to evade ...

Deadlock Avoidance It's a method to evade deadlock by careful resource scheduling. This approach to the deadlock problem foresees deadlock before it actually occurs. This a

Capability lists are typically kept within the address space, Q. Capabilit...

Q. Capability lists are typically kept within the address space of the user. How does the system make sure that the user cannot modify the contents of the list? Answer: An ap

Explain the booting process for a windows xp system, Q. Explain the booting...

Q. Explain the booting process for a Windows XP system? Answer: (1) Since the hardware powers on the BIOS begins executing From ROMand loads as well as executes the bootstrap

Quick, why we say " OS is a resource allocator" and “OS is a control progr...

why we say " OS is a resource allocator" and “OS is a control program"?

Explaintable management techniques, Discuss in detail Table management Tech...

Discuss in detail Table management Techniques?     An Assembler employs the subsequent tables: OPTAB: Operation Code Table consists of mnemonic operation code and its machi

Write a brief note on demand paging, Write a brief note on demand paging. ...

Write a brief note on demand paging. A demand paging is alike to a paging system with swapping. The Processes reside on the secondary memory while we want to implement a proces

Find the optimal solution and optimal value, Find the optimal solution and ...

Find the optimal solution and optimal value of the following linear program. Use both (a) the enumerating the corner points method and (b) the iso-profit line method. Also identify

Define abbreviation of sstf, SSTF stands for Abbreviation of SSTF is S...

SSTF stands for Abbreviation of SSTF is Shortest-Seek-time-first scheduling

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