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

Explain combined ult/klt approaches, COMBINED ULT/KLT APPROACHES Idea i...

COMBINED ULT/KLT APPROACHES Idea is to merge the best of both approaches Solaris is an illustration of an OS that combines both ULT and KLT  Thread creation complete i

How is a process chosen for being swapped either in or out?, How is a proce...

How is a process chosen for being swapped either in or out? Swap out: a.         If the process is idle. b.         If process has been in main memory for a long time.

What are the three main activities of an operating system, What are the thr...

What are the three main activities of an operating system in regard to memory management? Keep track of which parts of memory are now being used and by whom. Decide which pr

What is the basic approach of page replacement, What is the basic approach ...

What is the basic approach of page replacement? If no frame is free is available, find one that is not presently being used and free it. A frame can be freed by writing its con

Modern os, importance of Operating system in modern computers. Also explain...

importance of Operating system in modern computers. Also explain various functions & types of operating systems

Describe the purpose of the checkpoint mechanism, Describe the purpose of t...

Describe the purpose of the checkpoint mechanism. How habitually must checkpoints be performed? Explain how the frequency of checkpoints affects: System performance while no

What is an acyclic graph, What is an acyclic graph? A tree that has bee...

What is an acyclic graph? A tree that has been corrupted by links to other branches, but does not have any cyclic paths in it.

Independent process, what is independent process? distinguished between ind...

what is independent process? distinguished between independent process and co-operating process

Explain the different sections of a process., Explain the different section...

Explain the different sections of a process.     Entry section     Critical section     Exit section     Remainder section Consider a system inclusive of n processe

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