1.1 Systems architecture Webpage Mapping
The purpose of the CPU
Von Neumann architecture:
o MAR (Memory Address Register)
o MDR (Memory Data Register)
o Program Counter
o Accumulator
Common CPU components and their function:
o ALU (Arithmetic Logic Unit)
o CU (Control Unit)
o Cache
The function of the CPU as fetch and execute instructions stored in memory
How common characteristics of CPUs affect their performance:
o clock speed
o cache size
o number of cores
Embedded systems:
o purpose of embedded systems
o examples of embedded systems
Covered in the following ‘Revision Zones’:


Function of the CPU

Von Neumann Architecture

CPU Characteristics

1.2 Memory
The difference between RAM and ROM
The purpose of ROM in a computer system
The purpose of RAM in a computer system
The need for virtual memory
Flash memory.
 Covered in the following ‘Revision Zone’:


1.3 Storage
The need for secondary storage
Data capacity and calculation of data capacity requirements
Common types of storage:
o optical
o magnetic
o solid state
Suitable storage devices and storage media for a given application, and the advantages and disadvantages of these, using characteristics:
o capacity
o speed
o portability
o durability
o reliability
o cost.
 Covered in the following ‘Revision Zone’:


1.4 Wired and Wireless Networks
Types of networks:
o LAN (Local Area Network)
o WAN (Wide Area Network)
Factors that affect the performance of networks
The different roles of computers in a client-server and a peer-to-peer network
The hardware needed to connect stand-alone computers into a Local Area Network:
o wireless access points
o routers/switches
o NIC (Network Interface Controller/Card)
o transmission media
The internet as a worldwide collection of computer networks:
o DNS (Domain Name Server)
o hosting
o the cloud
The concept of virtual networks.
 Covered in the following ‘Revision Zones’:

Local Area Networks

Wide Area Networks

1.5 Network Topologies, Protocols and Layers
Star and mesh network topologies
o frequency and channels
o encryption
The uses of IP addressing, MAC addressing, and protocols including:
o TCP/IP (Transmission Control Protocol/Internet Protocol)
o HTTP (Hyper Text Transfer Protocol)
o HTTPS (Hyper Text Transfer Protocol Secure)
o FTP (File Transfer Protocol)
o POP (Post Office Protocol)
o IMAP (Internet Message Access Protocol)
o SMTP (Simple Mail Transfer Protocol)
The concept of layers
Packet switching.
 Covered in the following ‘Revision Zone’:

Ethernet, WiFi, Protocols

1.6 System Security
Forms of attack
Threats posed to networks:
o malware
o phishing
o people as the ‘weak point’ in secure systems (social engineering)
o brute force attacks
o denial of service attacks
o data interception and theft
o the concept of SQL injection
o poor network policy
Identifying and preventing vulnerabilities:
o penetration testing
o network forensics
o network policies
o anti-malware software
o firewalls
o user access levels
o passwords
o encryption.
 Covered in the following ‘Revision Zone’:

System Security

1.7 System Software
The purpose and functionality of systems software
Operating systems:
o user interface
o memory management/ multitasking
o peripheral management and drivers
o user management
o file management
Utility system software:
o encryption software
o defragmentation
o data compression
o the role and methods of backup:
– full
– incremental.
 Covered in the following ‘Revision Zones’:

Operating Systems

Utility Software

1.8 Computer Science Issues
How to investigate and discuss Computer Science technologies while considering:
o ethical issues
o legal issues
o cultural issues
o environmental issues
o privacy issues.
How key stakeholders are affected by technologies
Environmental impact of Computer Science
Cultural implications of Computer Science
Open source vs proprietary software
Legislation relevant to Computer Science:
o The Data Protection Act 1998
o Computer Misuse Act 1990
o Copyright Designs and Patents Act 1988
o Creative Commons Licensing
o Freedom of Information Act 2000.
 Covered in the following ‘Revision Zone’:



2.1 Algorithms  Webpage Mapping
Computational thinking:
o abstraction
o decomposition
o algorithmic thinking
Standard searching algorithms:
o binary search
o linear search
Standard sorting algorithms:
o bubble sort
o merge sort
o insertion sort
How to produce algorithms using:
o pseudocode
o using flow diagrams
Interpret, correct or complete algorithms.
 Covered in the following ‘Revision Zones’:

Computational Thinking

Search Algorithms

Bubble Sort

Merge Sort

Insertion Sort

Writing Algorithms


2.2 Programming Techniques
The use of variables, constants, operators, inputs, outputs and assignments
The use of the three basic programming constructs used to control the flow of a program:
o sequence
o selection
o iteration (count and condition controlled loops)
The use of basic string manipulation
The use of basic file handling operations:
o open
o read
o write
o close
The use of records to store data
The use of SQL to search for data
The use of arrays (or equivalent) when solving problems, including both one and two dimensional arrays
How to use sub programs (functions and procedures) to produce structured code
The use of data types:
o integer
o real
o Boolean
o character and string
o casting
The common arithmetic operators
The common Boolean operators.
 Covered in the following ‘Revision Zones’:

Variables & Data Types

Program Flow

Operations and String Manipulation

File Handling

Records & SQL


Procedures & Functions

2.3 Producing Robust Programs
Defensive design considerations:
o input sanitisation/validation
o planning for contingencies
o anticipating misuse
o authentication
o comments
o indentation
The purpose of testing
Types of testing:
o iterative
o final/terminal
How to identify syntax and logic errors
Selecting and using suitable test data.
 Covered in the following ‘Revision Zones’:

Defensive Design


2.4 Computational Logic
Why data is represented in computer systems in binary form
Simple logic diagrams using the operations AND, OR and NOT
Truth tables
Combining Boolean operators using AND, OR and NOT to two levels.
Applying logical operators in appropriate truth tables to solve problems
Applying computing-related mathematics:
o +
o –
o /
o *
o Exponentiation (^)
 Covered in the following ‘Revision Zone’:


Operations and String Manipulation

2.5 Translators and Facilities of Languages
Characteristics and purpose of different levels of programming language, including low-level languages
The purpose of translators
The characteristics of an assembler, a compiler and an interpreter
Common tools and facilities available in an integrated development environment (IDE):
o editors
o error diagnostics
o run-time environment
o translators.
 Covered in the following ‘Revision Zone’:

Translators & IDEs

2.6 Data Representation

Bit, nibble, byte, kilobyte, megabyte, gigabyte, terabyte, petabyte
How data needs to be converted into a binary format to be processed by a computer.

How to convert positive denary whole numbers (0-255) into 8 bit binary numbers and vice versa
How to add two 8 bit binary integers and explain overflow errors which may occur
Binary shifts
How to convert positive denary whole numbers (0-255) into 2 digit hexadecimal numbers and vice versa
How to convert from binary to hexadecimal equivalents and vice versa
Check digits.

The use of binary codes to represent characters
The term ‘character-set’
The relationship between the number of bits per character in a character set and The number of characters which can be represented (for example ASCII, extended ASCII and Unicode).

How an image is represented as a series of pixels represented in binary
Metadata included in the file
The effect of colour depth and resolution on the size of an image file.

How sound can be sampled and stored in digital form
How sampling intervals and other factors affect the size of a sound file and the quality of its playback:
o sample size
o bit rate
o sampling frequency.

Need for compression
Types of compression:
o lossy
o lossless

 Covered in the following ‘Revision Zones’:


Binary Numbers