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

Command interpreters, Develop a user mode command interpreter which support...

Develop a user mode command interpreter which support these functions: "list-short" -- just like ls without any options "list-long" -- same as ls -l "change" -- same as cd Your co

What is a reference string, What is a reference string? An algorithm is...

What is a reference string? An algorithm is evaluated by running it on a particular string of memory references and computing the number of page faults. The string of memory re

What is a semaphore, What is a semaphore? A semaphore 'S' is a synchron...

What is a semaphore? A semaphore 'S' is a synchronization tool which is  an integer value that, apart from initialization, is accessed only by two standard atomic operations; w

Describe two segment-replacement algorithms, Q. Segmentation is alike to p...

Q. Segmentation is alike to paging but uses variable-sized "pages". Describe two segment-replacement algorithms based on FIFO and LRU page replacement schemes. Remember that since

Unix script, As a group, you may need to make some enhancements to your dev...

As a group, you may need to make some enhancements to your development server (NOT your stable server!)  It needs to be able to run the makepasswd program, which may require instal

File management, approaches to identify free memory area in a heap

approaches to identify free memory area in a heap

Define field that contain segment index or an internal index, The field tha...

The field that consists of a segment index or an internal index is known as Target datum is field that consists of a segment index or an internal index.

Relationship among the capabilities of domain level j and i, Q. In a ring-...

Q. In a ring-protection system the level 0 has the greatest access to objects and level n (greater than zero) has fewer access rights. The access rights of a program at a partic

Example of producer consumer - semaphore, Now let's implement bounded produ...

Now let's implement bounded producer-consumer with semaphores, a Coke machine which is initially empty: semaphore sem_mutex = 1 // binary semaphore for mutual exclusion, 1==unlo

Several cpu-scheduling algorithms, Q. Several CPU-scheduling algorithms are...

Q. Several CPU-scheduling algorithms are parameterized for instance the RR algorithm requires a parameter to indicate the time slice. Multilevel response queues require parameters

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