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.
Q. Suppose an operating system maps user-level threads to the kernel utilizing the many-to-many model where the mapping is done through the use of LWPs. In addition the system allo
What is a sequential file? A file that is read one record or block or parameter at a time in order, based on a tape model of a file.
Discuss the risks of having a single root user
Q. Consider a file at present consisting of 100 blocks. Presume that the file control block (and the index block in the case of indexed allocation) is already in memory. Compute h
What is paging? Paging is a memory management scheme that authorizes the physical-address space of a process to be noncontiguous. Paging evades the considerable problem of fi
Describe swapping technique in UNIX systems. Swapping is used to control memory contention among processes. If there is excessively much memory contention, processes are swappe
Question: (a) Write down short notes on the different versions of Windows server 2003 mentioned below: 1. Windows Server 2003, Web Edition 2. Windows Server 2003, Stand
A- Consider a computer system that provides a virtual memory space that consists of 8 pages. The physical memory contains 4 pages where the page size is 4Kbytes. Assume that at sp
What is starvation? A main problem related to deadlock is starvation. Starvation is the circumstances where process waits indefinitely within the semaphore. Indefinite blocking
time-stamping It is a method proposed by Lamport, used to sequencing events in a distributed machine without the use of clocks. This process is intended to order events consis
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