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!
Consider a large web-based database. In some sense, Google is sort of like this. There might be many users who want to read from the database, but only a few users who are allowed to write to the database. If we use standard locks to control access to the database, the application will be much slower than it could be with a more clever type of lock.
Suppose we have one object that is shared among several threads. Suppose also that each thread is either a reader or a writer. Readers only read data but never modify it, while writers read and modify data. If we know which threads are reading and which ones are writing, what can we do to increase concurrency?
First, we have to prevent two writers from writing at the same time. In addition, a reader cannot read while a writer is writing. There is no problem, however in allowing lots of readers to read at the same time. Read-write locks achieve this, and can greatly improve performance for this sort of application.
Note that the lock is the same for both readers andwriters (called 'rw' in the slides), but the readers use an rlock() on the lock and writers use a wlock() on the same lock. Writers requesting a wlock() will have to wait until all readers and writers have released the lock. Readers requesting a rlock() can acquire it even if other readers are holding the lock. Readers however will still have to wait until any writer holding the lock releases the lock.
Q. Why is it important to scale up system bus and device speeds as the CPU speed increases? Answer: Consider a system which carries out 50% I/O and 50% computes. Doubling-up
Q. Consider the following page-replacement algorithms. Rank the algorithms on a five-point scale from "bad" to "perfect" according to their page-fault rate. Detach those algorithm
Q. What merit is there in having different time-quantum sizes on different levels of a multilevel queuing system? Answer: Processes that require more frequent servicing for ins
Before proceeding with its execution, every process must obtain all the resources it needs is called Hold and wait
Q. What are the three major purposes of an operating system? Answer: To offers an environment for a computer user to execute programs on computer hardware in a conveni
Question 1 Describe about the shells of Linux operating system Question 2 Describe briefly about GNOME desktop Question 3 Write note on the following- Encryp
Define properties of Distributed operating system Distributed:- This system distributes computation among several physical processors. The processors do not share memory or a
College life is tough. Eating pizza for every meal is hitting you hard. You are looking at working out to stay healthy. You found a web site that tells you how many calories eac
Translation Look aside Buffer In a cached system, the base addresses of the last few indexed pages is maintained in registers named the TLB that adds in faster lookup. TLB has
copy-on-write
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