XML CO527 Anonymous Questions and Answers Keyword Index

This page provides a keyword index to questions and answers. Clicking on a keyword will take you to a page containing all questions and answers for that keyword, grouped by year.

To submit a question, use the anonymous questions page. You may find the keyword index and/or top-level index useful for locating past questions and answers.

Keyword reference for processes

Question 19 (2010):

Submission reference: IN2023

Hi, I'm looking at the past exam paper for 2009 and for Q2 Part C I am unsure of the answers. I've made a guess of what states are represented by X, Y and Z and as for the other parts of the Q I am completely at a loss for where to look for answers/how to analyse the data I've been given in the Q for all the remaining parts. For questions like this what do we need to look for to figure out if it is preemptive or non-preemptive scheduling? I would hope the answer is not actually "it is impossible to tell" for this Q but if it is, how would I be able to tell if it were possible? Thanks.

Answer 19:

In this particular case, any of the three is possible. The 3 marks come from your justification of why, which may depend on your answers for the previous two parts. Arguing for "impossible to tell" is probably the hardest to do convincingly. Arguing for "non-preemptive" is probably the easiest. Obviously you need to know what preemptive scheduling is and how it affects the scheduling of processes in response to particular events.

Keywords: exams , processes

Referrers: Question 23 (2010)

Question 14 (2010):

Submission reference: IN2000

Hello, what are the three main states in which a process could exist? As far I know a process could be in a running state, blocked state and I am not sure about the last one. I am guessing it is either descheduled or sleep-state. Thanks.

Answer 14:

A sleep-state implies the process is waiting for something, and is thus blocked. The first two states (running and blocked) are two of them. The third is on run-queue, where the process is ready to run but the CPU is busy executing another process (one that must be in the running state). The term 'descheduled' would normally be used to describe the transition between states (e.g. running-to-blocked or running-to-run-queue).

Keywords: processes