Computer Systems
Examination Format & Preparation
Examination Process
• The January exams for all modules will take place online. Notes:
• The exams will become available in a new dedicated module in Canvas on:
• 11 January at 12.00 Midday(BST).
• You will have 72 hours to complete the exams,
• which will end on 14 January at 1200 Midday (BST).
• You will be sent a link to access this Canvas module before
the exams go live.
• You will download a PDF file consisting of a booklet of exams for each module.
• You may ONLY answer exam questions for modules that you are registered for.
• Answers to other exam questions will not be marked.
• Module leaders will be available online for questions for at
least the first two hours from when the exam goes live.
• The answers for each exam should be prepared in a separate PDF document.
• For each exam, there will be a separate Canvas assignment.
• You upload your answers for each exam to the corresponding Canvas assignment.
• Prepare your answers in a word processor and generate a .pdf document
• You can include images etc. as necessary
• You must make sure that everything is easily readable
• Your answers must be entirely your own work
Module Content
Numbers
Memory, CPU & Program Execution Instructions Assembly and Machine Code
High and low level; Compilation and Interpretation Subroutines and Stacks
Java Virtual Machine (JVM) and Bytecode
Efficiency (Algorithm Complexity)
Introduction to OS and its Elements
Computer Systems Architecture and OS Structures
Process Management Process Scheduling
Multithreading and its Challenges Concurrency and Synchronization Deadlocks
Introduction to Networks Application Layer
Transport Layer Network Layer Network Security
Preparing for examinations
• Understand the course content
• Study
• Revisit exercises & Quizzes
• Look at previous papers
• Make sure that you are in a fit state to take the exam:
• Concentrate & focus
• Sleep well
• …….
• Read the Questions:
• What is being asked?
• What is the weighting of parts?
• Answer the questions
• Completely!
• Give 3 Reasons …..
• And that they are different
• Using Examples …..
• Compare and contrast/Advantages and Disadvantages
• Be explicit!
• Don’t assume that marking is done globally:
• You might say X in Q1 ii) – but that will not get you credit
in Q2 iii) !
• Make sure your answer is clear, understandable, legible ……
• Think about the question & your answer from the examiners’ perspective!
Format of examination
• 3 questions
• Answer all questions
• Each question may have subparts
• These subparts may not be related
• There will NOT be any ‘recall’ questions:
• All questions expect you to apply your understanding
• Every paper is marked out of 60
• Each question carries 20 marks
• The marks for each subpart: • May vary
• Are shown explicitly
• The overall mark (out of 60) is
scaled to a percentage
• Overall grade:
• 50% Examination
• 50% Continuous Assessment
Computer Systems Sample Questions
Example Question #1
The diagram below shows roads connecting towns near to Rochdale. The numbers on each arc represent the time, in minutes, required to travel along each road. Peter is delivering books from his base at Rochdale to Stockport. Use Dijkstra’s algorithm to find the minimum time for Peter’s journey.
Example Question #2
Consider that you live in a small town where only dial-up access is available, with a maximum possible speed of 300-Kbps (using V.44 modems). You are interested in uploading a large video file of 2 gigabytes to a server on the Internet.
A bus visits your town everyday from the closest city, which is located at 210km away, and stops in front of your house for 5 minutes max (but it can leave as soon you indicate you are done). The bus has a 100-Mbps WiFi connection and it can collect data from users in rural areas and transfer them to the Internet through a 2-Gbps link once it gets back to the city.
Suppose the average speed of the bus is 70 km/h. What is the fastest way the user can transfer the data to the server?
Example Question #3
You are designing a network for a multinational corporation with offices in 50 different countries. Each office is required to be on a different subnet and the corporation has obtained a Class B network address of 150.32.0.0.
Design subnets for all of the site offices and indicate how many hosts (usable ones) can be assigned to each site office. Also, indicate if there is any room for expansion to 10 more countries, using the same network IP address and subnetting scheme.
You are not required to list all subnets, however, you can mention the subnet addresses, subnet masks and host address ranges for the first three and last subnet.
Example Question #4
Consider the block cipher shown in the following figure.
(see the question in the next slide)
Example Question #4 (contd)
Suppose that each block cipher Ti simply reverses the order of the eight input bits (so that, for example, 11110000 becomes 00001111).
Further suppose that the 64-bit scrambler does not modify any bits (so that the output value of the mth bit is equal to the input value of the mth bit).
(a) With n = 3 and the original 64-bit input equal to 10100000 repeated eight times, what is the value of the output?
(b) Repeat part (a) but now change the last bit of the original 64-bit input from a 0 to a 1.
(c) Repeat parts (a) and (b) but now suppose that the 64-bit scrambler inverses the order of the 64 bits.
Questions?
• Post in the chat