transition 2020 - y11 into y12...transition 2020 – y11 into y12 computer science a-level 3 types...

Transition 2020 - Y11 into Y12

Computer Science A-level

A-Level Computer Science qualification helps students understand the core academic principles of computer science. Classroom learning is transferred into creating a real-world solution through the creation of an independent programming project. A-Level will develop the student’s technical understanding and their ability to analyse and solve problems using computational thinking.

Section A: There are 4 theory topics to explore: ❏ Study the presentation for each topic

❏ Watch the video clips

❏ Answer the questions in the booklet

CompSci Alevel_Transition 2020 HHS STUDENT BOOKLET.docx

NB You will need to be signed in with your haslingdenhigh.com account on your device to access the

links to presentations, and have access to YouTube for the video clips.

1. Components of a computer

Types of processor Presentation: Computer Components T3 Types of processor.pptx Describe von Neumann, Harvard and contemporary processor architecture Describe the differences between, and uses of, CISC and RISC processors Describe GPUs and their uses Describe multicore and parallel systems https://www.youtube.com/watch?v=-P28LKWTzrI

2. Systems software and application generation

Types of operating system Presentation: Systems software T2 Types of OS.pptx Describe distributed, embedded, multi-tasking, multi-user and real-time operating systems Describe BIOS, device drivers and virtual machines https://www.youtube.com/watch?v=MJ2k71Ydwmk

https://drive.google.com/open?id=1bi2mF3_mlcN1MOutuYT6ZtZemo_zk-Xj

https://drive.google.com/open?id=1wHY6kyZo0M8g_QHS7icHG9tN8DFZR2Nw

https://www.youtube.com/watch?v=-P28LKWTzrI

https://drive.google.com/open?id=1WcMBrid_7G--Y5mkdqx3xTrD38V_OqSn

https://www.youtube.com/watch?v=MJ2k71Ydwmk

3. Networks and web technologies

Internet security Presentation: Networks T3 Network security and threats.pptx Discuss network security and threats Discuss use of firewalls, proxies and encryption Discuss worms, Trojans and viruses and the vulnerabilities that they exploit https://www.youtube.com/watch?time_continue=7&v=5geL5yHpa2Q&feature=emb_logo

4. Computational Thinking

Thinking abstractly Presentation: Computational thinking T1 Thinking abstractly.pptx

Understand the nature of and need for abstraction Describe the differences between an abstraction and reality Devise an abstract model for a variety of situations

https://www.physicsandmathstutor.com/computer-science-revision/a-level-ocr/elements-of-computational-thinking/thinking-abstractly-videos/

Section B: Practical programming is an essential component of the course: https://pythonschool.net/basics/introduction-to-python/

a. Complete the “Basics” section b. Move on to “Data Structures and Algorithms”

If you don’t already have Python IDLE installed on your computer, it’s free! Just download the latest version: https://www.python.org/downloads/

https://drive.google.com/open?id=1-Aa7eqamurOjyluQJKb8GNorm0cqpu7H

https://www.youtube.com/watch?time_continue=7&v=5geL5yHpa2Q&feature=emb_logo

https://drive.google.com/open?id=1rRIVw4Nc5A59P61D2ayRkJz7doPMumIy



https://pythonschool.net/basics/introduction-to-python/

https://www.python.org/downloads/

Transition 2020 – Y11 into Y12 Computer Science A-level

1

Types of processor

Task 1

1. Using standard von Neumann architecture, instructions and data both share the same memory space.

Memory

Address Instruction / Data

0 10010111 00101111

1

2 00000000 11010100

… …

255 00000000 01001010

One problem with this model is that the CPU can either be reading an instruction or reading/writing data to or from memory, but not both at the same time since instructions and data use the same bus system, which is a performance limitation.

(a) Name another architecture that resolves this issue. How does it differ from von Neumann architecture?

(b) What other advantages are there of using this architecture?

(c) What are the advantages of von Neumann architecture over Harvard architecture?


2

2. Complete the following text by using the words an phrases given below to fill in the gaps.

CISC stands for ____________________________. In this technology, the

________________ consists of a ________________ number of instructions,

each designed to execute a series of ________________ that make up a single

________________. Because the code is relatively ________________,

________________RAM is needed to store the instructions.

________________ stands for Reduced Instruction Set Computer. This type of

computer uses a ________________ instruction set, and each instruction can

be performed in one ________________. This means that ________________

is possible, and ________________ is at least as good or better than CISC.

Cheap ________________ has contributed to the prevalence of this

technology in almost all modern desktop computers.

pipelining short large clock cycle performance very little sub-tasks instruction

instruction set Complex Instruction Set Computer small RAM RISC

Task 2

Compare co-processor and parallel processor systems. (Note that “compare” means describe similarities and differences.)


3

Types of processor - extension

1. a) A low-cost von Neumann machine has an address bus of 16 bits. In this computer, a unit of addressable memory is two bytes. How many KiB of addressable memory can be used? [1]

b) (i) Explain the basic difference between von Neumann architecture and Harvard architecture. [2]

(ii) Why is Harvard architecture potentially able to achieve higher processing speeds than von Neumann architecture? [1]

(iii) Give a typical use of each type of architecture. [2]

2. Compare the features of a Reduced Instruction Set Computer (RISC) architecture with that of Complex Instruction Set Computer (CISC) architecture, stating one advantage of each. [6]

3. Describe briefly the features of a Graphics Processing Unit (GPU), stating why it is particularly suitable for image processing. [3]


4

Types of Operating System

Task 1

1. (a) In mobile operating systems, why do you think underlying hardware is handled by a low level proprietary OS, made and owned by the hardware manufacturer, and the user interface and applications are handled separately?

(b) Why do mobile devices such as smartphones and tablets require a different operating system from a desktop computer?


5

Task 2

2. (a) Match up the statements with the correct type of Operating System(s) that they relate to. Some statements may relate to more than one type of operating system.

• Distributed

• Embedded

• Multi-tasking

• Multi-user

• Real-time

A mainframe computer’s processing power is used by lots of individual terminals

A single job can be processed using the resources of multiple computers

Processor time is scheduled according to an algorithm

Inputs must be acted upon very quickly by the operating system

A household appliance might use this type of Operating System

A home desktop computer might have this type of operating system

Hardware redundancy and fail safes are required if the system is safety-critical

This type of OS gives the illusion of working with a single processor, when in reality jobs are coordinated across multiple computers

(b) Write down two more statements which relate to a type of operating system. Either in a group or with a partner, see if another student can work out which type of operating system your statement relates to.


6

Types of Operating System - extension

Task 1

1. (a) In mobile operating systems, why do you think underlying hardware is handled by a low level proprietary OS, made and owned by the hardware manufacturer, and the user interface and applications are handled separately?

(b) Why do mobile devices such as smartphones and tablets require a different operating system from a desktop computer?


7

Task 2

2. (a) Match up the statements with the correct type of Operating System(s) that they relate to. Some statements may relate to more than one type of operating system.

• Distributed

• Embedded

• Multi-tasking

• Multi-user

• Real-time

A mainframe computer’s processing power is used by lots of individual terminals

A single job can be processed using the resources of multiple computers

Processor time is scheduled according to an algorithm

Inputs must be acted upon very quickly by the operating system

A household appliance might use this type of Operating System

A home desktop computer might have this type of operating system

Hardware redundancy and fail safes are required if the system is safety-critical

This type of OS gives the illusion of working with a single processor, when in reality jobs are coordinated across multiple computers

(b) Write down two more statements which relate to a type of operating system. Either in a group or with a partner, see if another student can work out which type of operating system your statement relates to.


8

Internet security

Task 1 You are responsible for the network security of a new company with one office. It is suggested that a firewall and proxy server are required for the new system. Describe the role of a firewall in providing security. What function does a proxy server serve, and can it provide additional security?

Task 2

All employees use their own devices in the office. The company owner wants to make new employees aware of the best practices for preventing the intrusion of malicious software into the network. Write an overview that can be used to educate these new employees. You should explicitly mention:

• Preventing viruses

• Preventing worms

• Minimising the chance of phishing


9

Task 3 Social engineering is ‘blagging’ or tricking an individual into divulging their confidential details or information. The two email examples below may have come from confidence tricksters with malicious intent.

• What signs can you spot within these phishing emails that indicate they may not be from the advertised sender?

• What might happen if you clicked on one of the links or opened the attachment? Trojans, or other malware may infect your computer.

Task 4 A University wants to set up and run a course on ‘How to create a computer virus’. Discuss whether this is ethical.


10

Internet security- extension

1. Two writers are sharing draft sections of a book they are collaborating on together electronically. They are concerned other people may intercept these communications and leak the material. Explain why encryption might be appropriate. [2]

2. Network security can be enhanced by the use of a firewall and a proxy server. a. Define what is meant by a firewall. [1]

b. Explain how content filtering within a proxy server can provide network security. [2]

3. Malicious software introduced to a network can cause damage to operating systems and data loss. a. Explain the differences between a Trojan, a virus and a worm. [2]

b. Describe three precautions that users can take to minimise the risk of introducing malicious software onto a single computer. [3]


11

Thinking abstractly

Task 1

1. Give examples of some problems which can be tackled by building models or computer simulations

2. What factors would be relevant in a financial model which calculates the likely annual profit in a new coffee shop?

What factors would be irrelevant?


12

Task 2

3. Solve this puzzle.

The answer to Roll 1 is: 4





What is the answer to Roll #6?

Why?

Roll 1

Roll 2

Roll 3

Roll 4

Roll 5

Roll 6


13

Thinking abstractly - extension 1. An algorithm is to be written to find the optimum route between two points.

(a) List three applications such an algorithm may be useful for. [3]

(b) How has abstraction been used to reduce the complexity of these applications? [3]

2. A team of developers is working on the design and implementation of a new school timetabling system. The team has been given data that the school administration felt might be useful for this task.

(a) Explain why it is necessary for the developers to use abstraction in solving the problem. [2]

(b) List five data items that would be relevant in designing this system. [5]

(c) List three data items that would be irrelevant, even though they may have been supplied by the school office. [3]

3. Police have have known for a long time that everyone’s shoeprint is unique. In some areas of the UK, about 70% of suspects’ shoeprints are scanned and compared with the ones left at the scene of crime.

(a) Identify one similarity and one difference between fingerprint scanning and shoeprint scanning. [2]


14

(b) Give one reason why shoeprint scanning may be less effective than fingerprint scanning in catching criminals. [1]

(c) Give one reason why shoeprint scanning may be more effective than fingerprint scanning in catching criminals. [1]

transition 2020 - y11 into y12...transition 2020 – y11 into y12 computer science a-level 3 types...

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