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

What is the design issues involved in segmentation?, SEGMENTATION HARDWARE ...

SEGMENTATION HARDWARE An execution to map two-dimensional user-defined addresses into one-dimensional physical addresses. This mapping is affected by means of segment table. Ev

Unix, UNIX Shell and History feature. 1.Creating a child process. 2.Creatin...

UNIX Shell and History feature. 1.Creating a child process. 2.Creating a history feature. With the notes under code. Its exactly "programming project 1 - Unix Shell and History Fea

What is spooling, What is spooling? Spooling overlaps the I/O of single...

What is spooling? Spooling overlaps the I/O of single job with the computation of other jobs.

Solve a generalized dining philosopher problem, In this project, you will i...

In this project, you will implement the Chandy and Misra's (CM) algorithm using POSIX Threads (Pthreads).   The algorithm  is a distributed algorithm to solve a generalized dining

Quick, why we say " OS is a resource allocator" and “OS is a control progr...

why we say " OS is a resource allocator" and “OS is a control program"?

Determine a parser which is a variant of top-down parsing, Determine a pars...

Determine a parser which is a variant of top-down parsing without backtracking Recursive Descend parser is a variant of top-down parsing without backtracking.

Explain general graph directory structure, General Graph Directory A s...

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

What is paging? , What is paging? Paging is a memory management schem...

What is paging? Paging is a memory management scheme that authorizes the physical-address space of a process to be noncontiguous. Paging evades the considerable problem of fi

Explain advantages and inconveniences of ult, ADVANTAGES AND INCONVENIENCES...

ADVANTAGES AND INCONVENIENCES OF ULT Advantages: Thread switching doesn't involve the kernel - no mode switching Scheduling is able to be application specific -

Least-recently used, LRU evicts the page which was last accessed the farthe...

LRU evicts the page which was last accessed the farthest into the past of any page resident in physical memory, i.e. the least-recently used page. LRU approximates OPT when the rec

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