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. What are the three main activities of an operating system in regard to secondary-storage management? Answer: 1) Free-space management 2) Storage allocation 3) Disk
describe competing process
Define the Server Communications Module or SCM The Server Communications Module (SCM) performs many necessary functions. The SCM responsible for establishing, maintaining, and
Synchronization can be achieved by means other than locks and condition variables. One alternative is semaphores. A semaphore is used to regulate traf?c in a critical section. A se
Explain a boot control block A boot control block can have the information required by the system to boot an operating from that partition. If the disk does not have an operati
What is the use of inter process communication. Inter process communication gives a mechanism to allow the co-operating process to communicate with each other and synchronies t
Consider a setting where processors are not associated with unique identifiers but the total number of processors is known and the processors are organized along a bidirectional ri
Q. Present an algorithm for reconstructing a logical ring after a process in the ring fails? Answer: Typically distributed systems utilize a coordinator process that performs
What is Two-level directory In the two-level directory structure every user has own user file directory (UFD). When a user jobs begins or a user logs in, the system's master fi
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