OCR 9-1 (J277) GCSE Computer Science

First teaching 2020, first examination 2022

1.1.1 Architecture of the CPU

Defining what is a computer system

• Computer system
• Input, process, output, storage
• Data bus

Common CPU components and their function

• Control unit
• ALU
• Registers
• Cache

Von Neumann architecture

• Von Neumann architecture
• MAR & MDR
• Program Counter
• Accumulator

Fetch-Decode-Execute cycle

• Registers involved
• Fetch, decode, execute cycle

1.1.2 CPU performance

CPU common characteristics

• Clock speed
• Multi-core processors
• Cache size

1.1.3 Embedded systems

Purpose, characteristics of embedded systems

• Introduction
• Features
• Microcontroller

1.2.1 Primary storage

Primary storage features

• Features
• RAM ROM Cache

1.2.2 Secondary storage

Secondary storage features

• Common types of storage
• Suitable devices
• How to choose

1.2.3 Units

Units of data storage

• Bit, nibble, byte
• Kilobyte, megabyte
• Terabyte, petabyte

1.2.4 Data storage

Binary numbers

• Number systems
• Digit position
• Converting between binary/denary
• Adding binary
• Binary shift
• Binary overflow

Hexadecimal numbers

• Hex symbols
• Converting between binary/hexadecimal
• Converting between denary / hexadecimal

Characters

• ASCII
• Character sets
• Unicode

Images

• Storing pixels
• Meta data
• Quality of image
• Size of image file

Sound

• What is sound
• Sample rate
• Bit depth
• Size of sound file

Compression

• Lossy compression
• Lossless compression

1.3.1 Networks and topologies

Types of network

• What is a network
• Home network
• Business network/denary
• LAN
• WAN

Performance factors

• Bandwidth
• Number of users
• Latency
• Error rate
• Wi-Fi performance

Roles of computers

• Client - Server
• Peer-to-peer

Hardware needed

• NIC
• Hub
• Switch
• Router
• Transmission media
• WAP and Wi-Fi

Internet technology

• DNS
• Hosting
• Cloud
• Web servers and clients

Network topology

• Star topology
• Mesh topology

1.3.2 Networks, protocols and layers

Modes of connection

• Wired - Ethernet
• Wireless - Wi-Fi
• Wireless - Bluetooth

Encryption

• Encryption methods
• Symmetric
• Public - Private key

IP and MAC addressing

• IP addressing
• MAC addressing

Common Protocols

• TCP/IP
• HTTP
• HTTPS
• FTP
• POP
• IMAP
• SMTP
• Layer concept

1.4.1 Network threats

Types of threats

• Malware
• Social engineering,phishing
• Brute force attack
• Denial of Service
• Data interception
• SQL injection

1.4.2 Prevention methods

Threat prevention methods

• Penetration testing
• Anti-malware software
• Firewalls
• User-access rights
• Passwords
• Encryption
• Physical security

1.5.1 Operating systems

Purpose and use of operating systems

• User interface
• Memory management, multitasking
• Peripheral management and drivers
• User management
• File management

1.5.2 Utility software

Purpose and use of utility software

• Encryption software
• Defragmentation
• Data compression

1.6.1 Ethical Legal

Ethical issues

• Digital divide
• Genetic screening
• Whistleblowers
• Drones
• Self-driving cars

Environment

• E-waste
• Sustainability
• Recycling
• Energy
• Earth monitoring
• The stakeholders

Privacy issues

• DNA profiling
• National ID cards
• CCTV
• Electronic tracking
• Earth monitoring
• Personal data
• Stakholder perspective

Cultural issues

• Anonimity issues
• Use of social media
• Health issues arising
• Citizen journalism
• Making popular videos

Legislation

• The Data Protection Act 2018
• Computer Misuse Act 1990
• Copyright Designs & Patents Act 1988
• Software licences - open, proprietary

2.1.2 Computational thinking

Principles of computational thinking

• Abstraction
• Decomposition
• Algorithmic thinking
• Structure diagrams
• Abstraction practice
• Input-process-output practice
• Decomposition practice
• Algorithm practice
• Pattern recognition practice

Writing pseudocode (including Python practice)

• Pseudocode
• Practice activities
• Exam Reference language
• Python practice

Using flowcharts

• Flowcharts
• Practice activities

2.1.3 Searching and sorting algorithms

Search algorithms

• Binary search
• Linear search

Sort algorithms

• Bubble sort
• Merge sort
• Insertion sort
• Practice questions

2.2.1 Programming Fundamentals

Variables and others

• Variables
• Constants
• Operators
• Assignments
• Input Output

Arrays

• One dimenstion
• Two dimension
• Static
• Dynamic
• Array functions

Sequence Selection Iteration

• Sequence
• Selection
• Iteration
• Conditionals - IF
• Conditionals - CASE
• WHILE iteration
• DO iteration
• FOR iteration

2.2.2 Data types

Use of data types

• Integer
• Real
• Boolean
• Character
• String
• Casting

2.2.3 Additonal programming

String manipulation and handling

• Assignment
• Concatenate
• Traversal
• Search
• Copy

File manipulation and handling

• Open
• Read
• Write
• Close

SQL and databases

• Records
• SQL
• SELECT
• WHERE
• FROM

Functions and subprocedures

• Repeating code
• Subprocedures
• Functions
• Code library

Random numbers

• Use of random numbers
• Python worked example
• Python files in zip

2.3.1 Defensive design methods

Defensive design

• User interface choice
• Screen widgets
• Repeat data entry
• Input boxes
• Validation
• Authentication

Maintainable code

• Comments
• Headers
• Whitespace
• Indentation
• Naming

2.3.2 Identify syntax and logic errors

Spotting errors

• Logic errors
• Syntax errors
• Arithmetic order
• Debugging tools
• Runtime errors
• Authentication

Types of testing

• Test plan
• Test data
• Black box strategy
• White box strategy
• Iterative testing
• Final testing

2.4.1 Boolean logic

Logic

• What is logic
• Binary logic
• Logic gates
• Truth tables
• Standard symbols

2.5.1 & 2.5.2 Languages & IDE

Languages

• Machine code
• Assembly language
• High level language
• Translator
• Compilers
• IDE features