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

Explain about functions of operating system, Q. Explain about Functions of ...

Q. Explain about Functions of Operating System? Functions of Operating System Operating system performs 3 functions as follows: 1.  Convenience:   Operating System mak

Read-write locks, Consider a large web-based database. In some sense, Googl...

Consider a large web-based database. In some sense, Google is sort of like this. There might be many users who want to read from the database, but only a few users who are allowed

Explain the demand paging system, Question : (a) In the demand paging ...

Question : (a) In the demand paging system, when a process tries to access a page that was not brought into memory, a page fault occurs that involves a series of actions. The

Write knowledge base relevant propositional statement, Suppose a logic-base...

Suppose a logic-based agent in the wumpus world has found that locations (1,1) and (2,1) do not contain a stench, but that locations (3,1) and (2,2) do contain a stench. Can the ag

Interprocess communication, Now we consider the following questions: how ca...

Now we consider the following questions: how can the parent process communicate with its child? Or how can children processes communicate with other children? The exact answer depe

File system, what are disadvantages of using single directory

what are disadvantages of using single directory

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. Its exactly "programming project 1 - Unix Shell and History Feature (p.157-159)" in the Si

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

Define thrashing, Define thrashing. Thrashing is the accident of high p...

Define thrashing. Thrashing is the accident of high page traffic and low CPU utilization. It is observed that the cause of thrashing is an under-commitment of memory to program

Socket, socket based fortune teller sever.your program should create a serv...

socket based fortune teller sever.your program should create a server that listens to a specific port when a client receives a connection the server should respond with a random fo

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