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.
Before proceeding with its execution, every process must obtain all the resources it needs is called Hold and wait
What problems arise if the directory structure is a general graph? Searching for a particular file may result in searching the similar directory many times. Deletion of the fil
What is Single-level Directory All files are constrained in the similar directory, which is simple to support and understood. One limitation is when the number of files enhance
Concept of Reentrancy It is a useful, memory-saving method for multiprogrammed timesharing machines. A Reentrant method is one in which multiple clients can share a singl
General Graph Directory A serious trouble with using an acyclic graph structure is making sure that there are no cycles. When links are further added to an existing tree struc
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. 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
Define the OS/2 threads code The sample program in Listing is very similar to the NetWare example. OS/2 commands are substituted for the pseudocode commands controlling thread
Write a short note on PCB? Every process is represented in the operating system by a process control block also called a task control block. It contains more information regard
Normal 0 false false false EN-IN X-NONE X-NONE MicrosoftInternetExplorer4
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