Explain a computing environment, Operating System

Assignment Help:

Q. Polling for an I/O completion is able to waste a large number of CPU cycles if the processor iterates a busy-waiting loop several times before the I/O completes. However if the I/O device is ready for service polling can be much more proficient than is catching and dispatching an interrupt. Explain a hybrid strategy that combines sleeping, polling, and interrupts for I/O device service. For every of these three strategies (pure polling, pure interrupts, hybrid) explain a computing environment in which that strategy is more efficient than is either of the others.

Answer: A hybrid approach could switch among polling and interrupts depending on the length of the I/O operation wait. For instance we could poll and loop N times and if the device is still busy at N+1 we could set an interrupt and sleep. This approach would evade long busy-waiting cycles. This process would be best for very long or very short busy times. It would be incompetent it the I/O completes at N+T (where T is a small number of cycles) because of the overhead of polling plus setting up and catching interrupts.

Pure polling is best with extremely short wait times. Interrupts are best with known long wait times.


Related Discussions:- Explain a computing environment

Program of calculator and controller - fork, Program of Calculator and Con...

Program of Calculator and Controller with the fork, exec, and wait system calls The objective of this assignment is to get you to be comfortable with the fork(), exec(), and wai

Virtual memory and paging, A- Consider a computer system that provides a vi...

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

Define overflow chaining, Define Overflow Chaining Another method will ...

Define Overflow Chaining Another method will divide the pre-allocated table into two sections: the primary area to determine which keys are mapped and an area for collisions, g

Thread safety, What does it mean for something to be thread-safe? By saying...

What does it mean for something to be thread-safe? By saying that X is thread-safe, we mean that if multiple threads use X at the same time, we don't have to worry about concurrenc

What is sector sparing, What is sector sparing? Low-level formatting al...

What is sector sparing? Low-level formatting also sets aside extra sectors not visible to the operating system. The controller can be told to change each bad sector logically w

Explain general graph directory, General graph directory The serious pr...

General graph directory The serious problem with using an acyclic-graph structure is ensuring that there are no cycles. When we insert links to an existing tree-structured dire

Difference between symmetric and asymmetric multiprocessing, Discuss differ...

Discuss difference between symmetric and asymmetric multiprocessing  Symmetric multiprocessing (SMP), in which every processor runs an identical copy of the operating system an

Socket, socket based fortune teller sever.your program should create a serv...

socket based fortune teller sever.your program should create a server that listens to a specific port when a client receives a connection the server should respond with a random fo

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

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!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd