Already have an account? Get multiple benefits of using own account!
Login in your account..!
Remember me
Don't have an account? Create your account in less than a minutes,
Forgot password? how can I recover my password now!
Enter right registered email to receive password!
Now, let us discuss two related algorithms for deciding which pages to evict. The clock algorithm is one of the most popular choices. It works by keeping frames in a circular structure. (Note that this circle may be very large: a 32-bit machine with 4k pages can have up to 220 1 million frames.) When a page fault occurs, it checks the reference bit of the next frame. If that bit is zero, it evicts that page and sets its bit to 1; if the reference bit is 1, the algorithm sets the bit to 0 and advances the pointer to next frame.
An implementation which is often used in real operating systems is a segmented queue. This type of algorithm divides all existing pages into two sets of pages. The most-active one-third of all pages use a clock algorithm. After that, pages that are evicted out of the clock are moved to a "uncommon" linked list, in which we use exact LRU. This way, we approximate LRU for the frequently-referenced pages (1/3 of the page frames - fast clock algorithm), and at the same time use exact LRU on the infrequently accessed pages (2/3 of all page frames). Since the pages in the uncommon list are not accessed very frequently, it is okay if their accesses are a little slower due to some pointer manipulation.
Hashed page tables A common approach for handling address spaces larger than 32 bits is to use a hashed page table. Every entry in the hash table having a linked list of elemen
how is it possible
Clocks in distributed systems : a. Why are clocks difficult to synchronize in distributed systems? b. What features in a system assume that the clocks are (reasonably) synchr
An operating system act as an intermediary between user of a computer and computer hardware. The objective of an operating system is to provide an environment in that a user can ex
Q. Does Windows XP offer any user-mode processes that enable it to run programs developed for other operating systems? Describe two of these subsystems. Answer: Environmental
What is single and multithreading and thread pool?
Discuss the risks of having a single root user
How is it different from the unbounded buffer algorithm ? Explain.
In modern operating systems, applications do not directly access the physical memory. Instead, they use so-called virtual memory, where each virtual address is translated to a phys
Many-to-One Model (Green Threads) Implementations of the many-to-one model a lot of user threads to one kernel thread permit the application to create any number of threads tha
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!
whatsapp: +91-977-207-8620
Phone: +91-977-207-8620
Email: [email protected]
All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd