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

Server thread, Extend task 1 so that the requests are issued by the clients...

Extend task 1 so that the requests are issued by the clients instead of the server. The server now do not use the "all_requests.dat" file. Instead every client thread reads from

Define what is dispatcher, Define what is Dispatcher In the Worker Mode...

Define what is Dispatcher In the Worker Model, it is the task of the Dispatcher to spawn a thread for every client-to-server connection. The Dispatcher acts as the go-between o

Obelia, what do obelia eat and how do they feed

what do obelia eat and how do they feed

What are the various file operations, What are the various file operations?...

What are the various file operations? The six basic file operations are Creating a file Reading a file Writing a file Repositioning within a file Tr

Multiprogramming, how response times are reduced by allowing time sharing o...

how response times are reduced by allowing time sharing on top of multiprogramming

An operating system for a real-time environment, Q. What is the major diffi...

Q. What is the major difficulty that a programmer should overcome in writing an operating system for a real-time environment? Answer: The major difficulty is keeping the oper

Discuss various services provided by the operating system, List and discuss...

List and discuss the various services provided by the operating system. Program execution - system capability to load a program into memory and to run it. I/O operatio

Explain c-scan , LOOK o Like SCAN except stops moving inwards (or outw...

LOOK o Like SCAN except stops moving inwards (or outwards) when no more requests in that direction exist. C-SCAN (circular scan) o Moves inwards servicing requests u

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