Identifying parallelism, Operating System

Assignment Help:

Identifying parallelism

A formal way to identify parallelism in an activity is to draw a task dependence graph in a directed graph in which each vertex represents a task to be completed. An edge from vertex u to vertex means that task u must be completed before task v begins, so that task v "depends on" u. If there is no path from u to v, then the tasks are independent and may be performed concurrently. Consider the following problem: Alice is the leader of a crew of workers who maintain a large estate. There are four principal tasks: mowing the lawns, pruning the trees and hedges, repairing the fences, and inspecting the work to ensure it has all been done satisfactorily. Mowing must be completed before the work is inspected, as must the pruning and fence repair. The estate has a security system which must be switched off before work commences (i.e. before Alice and her team arrives), and switched on again after the team leaves.

  • Draw the dependence graph corresponding to the above problem, showing all the tasks involved. (In a project management plan, this scheme is often referred to as a "work breakdown structure").
  • Alice has 8 people in her crew, including herself. (The crew members are: Alice, Bert, Cressida, Dominic, Edgar, Frank, Gus and Harriet). Alice will be solely responsible for inspecting the work, but decides that she herself and three other people (Bert, Dominic and Gus) will mow the estate's four lawns (referred to as north, south, west and east lawns, each of which are of equal area), two other people (Cressida and Frank) will prune the trees, whilst Edgar and Harriet will repair the fences. Redraw the graph to show the allocation of the crew to particular tasks. (Hint: a single task in the original graph may be come multiple tasks in the revised version, each of which is performed by a particular person).
  • Alice is a fast worker, and can mow any of the lawns in one hour, as can Dominic. Frank and Gus can complete any of the manual tasks in two hours. Bert, Cressida, Edgar and Harriet take three hours to do their work. If the manual work starts at 10:00 a.m. in the morning, at what time scan Alice inspect the work? In your answer, refer to the dependence graph showing the allocation of crew to tasks.

Since mowing is done first and then all team members start the work simuntaneosly and Alice can only inspect after each has finished their task the time taken by the slowest team members will be seen here.

Harriert/Bert/Credessia and Edgar take 3 hrs each to complete their task.

The manual work starts at 10.00 AM so the inspection will start 3+3 =6 hrs after that.


Related Discussions:- Identifying parallelism

What is the use of boot block, What is the use of boot block? For a com...

What is the use of boot block? For a computer to begin running when powered up or rebooted it requires having an initial program to run. This bootstrap program tends to be easy

Objectives and functions of an operating system, Question: a) What is ...

Question: a) What is an Input/Output module and what are the five categories their functions fall into? b) What is an Operating System? Briefly describe the two objectives

Explain deadlock, Explain Deadlock Every process in a set of processes ...

Explain Deadlock Every process in a set of processes is waiting for an event which only a process in the set can cause.

Define the conditions of deadlock prevention, What are the four necessary c...

What are the four necessary conditions of deadlock prevention?       Ans:  Four essential conditions for deadlock prevention: a. The meaning of removing the mutual exclusio

Design a android application, As mentioned earlier, the game engine will b...

As mentioned earlier, the game engine will be used as the base of developing the Go game for the Android. This includes improving logic of the game, design good graphics and optim

What is paging? name the different paging techniques, What is paging? Name ...

What is paging? Name the different paging techniques. Paging is a memory management method that permits the physical-address space of a process to be noncontiguous. Paging evad

Constructional techniques - copper clad circuit board, For the first assign...

For the first assignment you are required to construct a logic circuit onto a copper clad circuit board (vero board). This construction will require the use of planning the positio

Explain direct communication and indirect communication, Direct communicati...

Direct communication With direct communication each process that requires to communicate must explicitly name the recipient or sender of the communication. The send and receive

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