Computer Science — Year 11

 

Computer Science Overview
Curriculum

Term 1: Binary and Hexadecimal

In this unit students will learn how data is represented by the computer systems and why the binary systems is essential for computer processing. Students will learnt how to convert binary into denary and be able to carry out addition, subtraction, multiplication and division on binary numbers. Students will learn why hexadecimal numbers are used and how to convert between binary, denary and hexadecimal. Students will also learn about binary representation of characters, images and audio and how file compression reduces files.

Students will sit a written End of Unit assessment. This topic is part of Unit 2. Unit 2 is 40% of the whole qualification and is a 1 hour 30 minute written examination.

Denary numbers
“A numerical system of notation which uses 10 as its base. The 10 Decimal base digits are 0-9.”

Binary numbers
“Binary describes a numbering scheme in which there are only two possible values for each digit: 0 and 1. The term in computing refers to any digital encoding system in which there are exactly two possible states. E.g. in memory, storage, processing and communications, the 0 and 1 values are sometimes called “low” and “high”, respectively.”

Binary arithmetic
“The process of adding together two of more positive 8-bit binary numbers (0-255).”

Overflow
“The generation of a number that is too large to be represented in the device meant to store it.”

Hexadecimal
“A numerical system of notation which uses 16 rather than 10 as its base. The 16 Hex base digits are 0-9 and the letters A-F.”

Binary shifts
“Allows you to easily multiple and divide base-2 binary numbers. A left shift multiplies by 2 and a right shift divides by 2.

Character set
“The set of symbols that may be represented in a computer at a particular time. These symbols, called characters, can be letters, digits, spaces or punctuations marks, the set includes control characters.”

ASCII
“America Standard Code for Information Interchange: “A character set devised for early telecommunication systems but proved to be ideal for computer systems. ASCII codes use 7-bits giving 32 control codes and 96 displayable characters (the 8th bit is often used for error checking).”

Unicode
“Standard character set that replaces the need for all the different character sets. It incorporates characters from almost all the world’s languages. It is a 16-bit extension of ASCII.”

Pixels
“A pixel is the smallest unit of a digital image or graphic that can be displayed and represented on a digital display device. A pixel is represented by a dot or square on a computer monitor display screen.”

Metadata
“A set of data that describes and gives information about other data.”

Colour depth
“Also known as bit depth, is either the number of bits used to indicate the colour of a single pixel, in a bitmapped image or video frame buffer, or the number of bits used for each colour component of a single pixel.”

Resolution
“The number of pixels (individual points of colour) contained on a display monitor, expressed in terms of the number of pixels on the horizontal axis and the number on the vertical axis.”

Image quality
“The overall detail of an image, this is affected by the colour depth and resolution.”

Image file size
“The file size of an image is increased when either its resolution (width & height in pixels) or its colour depth (number of bits needed to store a single pixel) increases.File size of an image = colour depth x image height (px) x image width (px)

Sample rate
“The number of samples taken per second, measured in Hertz (Hz).”

Sample duration
“How many seconds of audio the sound file contains.”

Sample bit depth
“The number of bits available to store each sample e.g. 16-bit”

Playback quality
“The finished quality of the digital sound file. This is effected by the sample rate and bit-depth. The higher the number the better the quality. The higher the number the larger the file size. CD quality is 44,100 samples per second.”

Sound file size
“The overall size of a sound file is found by the following formula: Sample rate x duration (s) x bit depth

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Term 1: Computer Systems (Hardware and Software) and Networks,

Students will be able to explain what is meant by different types of computer systems and describe the structure of CPU and functions of components. They will understand the FDE cycle and the need to multiple cores, cache and virtual memory. Students will learn about systems software, operating systems and utility software. Students will learnt about different types of computer networks for different purposes and the functions of hardware required to connect computers. They will learn the differences between client servers and peer-to-peer networks, how data is transmitted across networks and the use of protocols to ensure integrity of data transmitted.

Students will sit a written End of Unit assessment. This topic is part of Unit 1. Unit 1 is 40% of the whole qualification and is a 1 hour 30 minute written examination.

LAN
Local Area Network: “Small geographic area. All the hardware for the LAN is owned by the organisation using it. Wired with UTP cable, fibre optic cable or wireless using routers and Wi-Fi access points.”

WAN
Wide Area Network: “Small geographic area. All the hardware for the LAN is owned by the organisation using it. Wired with UTP cable, fibre optic cable or wireless using routers and Wi-Fi access points.”

Client-server network
“A client makes requests to the server for data and connections. A server controls access and security to one shared file store. A server manages access to the internet, shared printers and email services. A server runs a backup of data.”

Peer-to-peer network
“All computers are equal. Computers serve their own files to each other. Each computer is responsible for its own security and backup. Computers usually have their own printer.”

Wireless access point
“A networking hardware device that allows a Wi-Fi device to connect to a wired network.”

Router
“A router sends data between networks. It is needed to connect a local area network to a wide area network. It uses the IP address on a device to route traffic to other routers.”

Switch
“A switch sends data between computers on a local area network. It uses the NIC address on a device to route traffic.”

NIC
Network Interface Card/Controller: “A computer hardware component that connects a computer to a computer network.”

Transmission media
“The physical media over which data is transmitted, e.g. twisted copper cable, fibre optic etc. ”

The Internet
“The Internet is a worldwide collection of interconnected computer networks. It is an example of a WAN, albeit the very largest one which exists!”

DNS
Domain Name System: “The Internet’s equivalent of a phone book. They maintain a directory of domain names and translate them to Internet Protocol (IP) addresses. This is necessary because, although domain names are easy for people to remember, computers or machines access websites based on IP addresses.”

Hosting
“Websites stored on dedicated servers. Reasons include: Websites need to be available 24/7. Accessed by thousands of users at a time. Strong protection from hackers. They need an IP address that doesn’t change.”

The Cloud
“Remote servers that store data that can be accessed over the internet. Advantages: Access anytime, anywhere from any device. Automatic backup. Collaborate on files easily.”

Web server
“A program that uses HTTP (Hypertext Transfer Protocol) to serve the files that form Web pages to users, in response to their requests, which are forwarded by their computers' HTTP clients. Dedicated computers and appliances may be referred to as Web servers as well.”

Client
“A client can be thought of as computing device which requests or is using the services from some remote / connected server.”

Network topology
“The physical or logical arrangement of connected devices on a network e.g. Computers, switches, routers, printers, servers etc.”

Star topology
“Computers connected to a central switch. If one computer fails no others are affected. If the switch fails all connections are affected.”

Mesh topology
“Switches (LAN) or routers (WAN) connected so there is more than one route to the destination. e.g. The Internet More resilient to faults but more cable needed.”

Wired connection
“Any physical connection made between two or more devices e.g. Copper wire, Ethernet cables, fibre optics etc.”

Ethernet
“A standard for networking local area networks using protocols. Frames are used to transmit data. A frame contains the source and destination address, the data and error checking bits. Uses twisted pair and fibre optic cables. A switch connects computers together.”

Wireless connection
“Any connection made between two or more devices which does not involve the need for a physical connection e.g. Wi-Fi, 4G, Bluetooth etc.”

Wi-Fi
“Wireless connection to a network. Requires a wireless access point or router. Data is sent on a specific frequency. Each frequency is called a channel.”

Bluetooth
“A method of exchanging data wirelessly over short distances, (much shorter than Wi-Fi). Examples of typical Bluetooth use could be, headphones, car mobiles etc.”

Encryption
“Encoding readable data called plaintext into unreadable data called ciphertext. Only the intended recipient can decode the data using a key. Protects communications from hackers.”

IP address
Internet Protocol Address: “A unique string of numbers separated by full stops that identifies each computer using the Internet Protocol to communicate over a network.”

MAC address
Media Access Control Address: “A unique identifier assigned to network interfaces for communications at the data link layer of a network segment. MAC addresses are used as a network address for most network technologies, including Ethernet and Wi-Fi.”

Standards
“The field of Computer Science is full of standards. They provide us with various rules for different areas of computing. Standards allow hardware and software to interact across the different manufacturers / producers.”

Protocol
“A set of rules that allow two devices to communicate.”

TCP/IP
Transmission Control Protocol / Internet Protocol: “TCP provides an error free transmission between two routers. IP routes packets across a wide area network.”

HTTP
Hypertext Transfer Protocol: “A client-server method of requesting and delivering HTML web pages. Used when the information on a web page is not sensitive or personal.”


HTTPS
Hypertext Transfer Protocol Secure: “Encryption and authentication for requesting and delivering HTML web pages. Used when sensitive form or database data needs to be transferred. e.g. passwords and bank account details.”

FTP
File Transfer Protocol: “Used for sending files between computers, usually on a wide area network. Typically used for uploading web pages and associated files to a web server for hosting.”

POP
Post Office Protocol: “Used by email clients to retrieve email from an email server.”

IMAP
Internet Message Access Protocol: “Used by mail clients to manage remote mailboxes and retrieve email from a mail server.”


SMTP
Simple Mail Transfer Protocol: “Sends email to an email server.”


Protocol layering
“The concept of a protocol not simply being a set of rules but those rules being built up into very specific layers and those rule layers behind built on top of each other in a deliberate order creating a layered protocol stack. This results in the rules of a protocol being executed in a specific sequence as you move through the protocol stack.”

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Develop the individual:

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Term 2: Systems Security

Students will be able to threats posed to networks and describe different strategies used by criminals to attack computer networks and how these threats can be identified prevented and combatted using network policies..

Students will sit a written End of Unit assessment. This topic is part of Unit 1. Unit 1 is 40% of the whole qualification and is a 1 hour 30 minute written examination.

Malware
“Software written to cause loss of data, encryption of data, fraud and identity theft: virus, worm, trojan, ransomware and spyware.”

Social engineering
“Most vulnerabilities are caused by humans. Not locking computers. Using insecure passwords. Not following/poor company network policies. Not installing protection software. Not being vigilant with email/files received. Not encrypting sensitive data.”

Phishing
“Sending emails purporting to be from reputable companies to induce people to reveal personal information.”

Brute-force attack
“A trial and error method of attempting passwords. Automated software is used to generate a large number of guesses.”

Denial of service attack
“Flooding a server with so much traffic it is unable to process legitimate requests.”

Data interception and theft
“Stealing computer-based information.”

SQL injection
“A hacking technique used to view or change data in a database by inserting SQL code instead of data into a text box on a form.”

Penetration testing
“Testing designed to check the security and vulnerabilities of a system.”

Anti-malware software
“Antimalware software protects against infections caused by many types of malware, including viruses, worms, Trojan horses, rootkits, spyware, key loggers, ransomware and adware.”

Firewall
“A computer application used in a network to prevent external users gaining unauthorised access to a computer system.”

User access level
“The amount of access a given user is allowed to a computer. On a network most users will have restricted access. Whereas a systems administer or network technician would be allowed much greater access with fewer restrictions.”

Password
“A secret word or phrase that must be used to gain access to a computer / program / interface / system.”

Physical security
“Any form of real world physical security to help protect data and systems e.g. Alarms, locks, security patrols etc.”

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Develop the individual:

Create a supportive community:

Term 2 - Term 5: Unit 3: Programming Project (NEA)

Start Date Monday 16th October 2017

Deadline Friday 8th December 2017

Non-Examined Assessment (NEA) is worth 20% of the overall grade and consists of a Programming Project.

OCR issue three assessment tasks at the start of Year 11. NEA must take place under supervision of the teacher and there are strict rules in place. Students are expected to create suitable algorithms that willprovide a solution to the problems identified in the task. They must then code their solution, producing a development diary to show progress. Finally student must test and evaluate the solution. Students are provided with the mark scheme and a bank of resources to support.

No Internet access is permitted during completion of the NEA.

There are five aspects to assessment of NEA reflecting three Assessment Objectives.

Programming Techniques - 12 marks - AO3

Analysis - 6 marks - AO2 and AO3

Design - 8 marks - AO1, AO2 and AO3

Development - 8 marks - AO1, AO2 and AO3

Testing and Evaluation - 6 marks - AO2 and AO3

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Develop the individual:

Create a supportive community:

Term 4 - Term 5: Ethical, Legal, Cultural and Environmental Concerns

In this unit, students will learn about impact of development of computer science technologies and be able to discuss environmental, ethical, legal and cultural issues. Students will also be able to describe the legislation relevant to computer science and the issues of data collection and privacy.

Students will sit a written End of Unit assessment. This topic is part of Unit 1. Unit 1 is 40% of the whole qualification and is a 1 hour 30 minute written examination.

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Develop the individual:

Create a supportive community:

Term 4 - Term 5: Preparation for Examinations

Students will prepare for examinations.

Unit 1: Computer Systems 1 hour 30 minutes examination. Monday 14th May 2018

Unit 2: Computational thinking, algorithms and programming 1 hour 30 minute examination. Wednesday 16th May 2018

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Develop the individual:

Create a supportive community: