Character Sets

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Character Sets

Text data is made up of characters. Character sets allow us to store characters digitally.

Character sets

Text data is made up of characters.
Each character is assigned its own character code.
A character set is a collection of all the characters that a computer recognises, along with their binary codes.

What's in a character set?

Character sets include:
- Alphanumeric characters e.g. letters, numbers, and symbols.
- Special characters e.g. new line.

Examples of character sets

There are two main character sets in use:
- American Standard Code for Information Interchange.
- Unicode.

American Standard Code for Information Interchange

The American Standard Code for Information Interchange (ASCII) character set is the most common character set.

ASCII

Each character in ASCII is represented by a seven-bit binary code.
- That means there is a maximum of 128 characters.
ASCII includes all commonly used letters and symbols in the English language.

7-bit letters?

Each letter is represented by seven bits.
This is useful because when used in an 8-bit system, the extra bit can be used as a check digit.

Limitations of ASCII

128 characters is perfectly fine for the English language. But it does not leave space for characters from other languages.
An extended ASCII set was released which used all eight bits, but it was still not enough.
This led to the release of Unicode.

Unicode

Unicode is a character set which was released because of the need to standardise character sets internationally.

Unicode

Unicode aims to represent every possible character in the world.
The most common form of Unicode is UTF-8 and uses between eight and 32 bit binary codes to represent each character.

Compatability with ASCII

The first 256 characters in Unicode are identical to extended ASCII, which makes it backwards compatible with documents encoded using older character sets.

Types of characters

Unicode represents characters from all major alphabets of the world.
Unicode is also used to represent emojis!

1Components of a Computer

1.1Structure & Function of the Processor

1.1.1Structure of the CPU

1.1.2Fetch, Decode, Execute Cycle

1.1.3Factors Affecting CPU Performance

1.1.4CPU Architecture

1.2Types of Processors

1.2.1CISC & RISC

1.2.2Multicore & Parallel Cores

1.3Input, Output & Storage

1.3.1Computer Systems

1.3.2Magnetic Storage

1.3.3Optical Storage

1.3.4Types of Optical Storage

1.3.5Types of Memory

1.3.6Flash Memory

1.3.7Virtual Memory

2Software & Software Development

3Exchanging Data

4Data Types, Data Structures & Algorithms

4.1Data Types

4.1.1Data Types

4.1.2Arrays & Strings

4.1.3Representing Numbers

4.1.4Binary Arithmetic

4.1.5Hexadecimal

4.1.6Converting Binary Numbers

4.1.7Floating Points in Binary

4.1.8Floating Point Arithmetic

4.1.9Bitwise Manipulation

4.1.10Character Sets

4.2Data Structures

4.2.1Arrays, Linked Lists & Queues

4.2.2Graphs, Hash Tables & Stacks

4.2.3Trees

4.3Boolean Algebra

4.3.1Computational Logic

4.3.2Boolean Logic

4.3.3Karnaugh Maps

4.3.4Boolean Identities

4.3.5Flip Flops & Adder Circuits

5Legal, Moral, Cultural & Ethical Issues

5.1Computing Related Legislation

5.1.1Data Protection Act (1998)

5.1.2Computer Misuse Act (1990)

5.1.3Copyright Designs and Patents Act (1988)

5.1.4Regulation of Investigatory Powers Act (2000)

5.2Moral & Ethical Issues

5.2.1Online Activity Tracking

5.2.2Censorship

5.2.3Cultural Issues

5.2.4Environmental Issues

5.2.5Layout, Colour Paradigms & Character Sets

6Elements of Computational Thinking

6.1Thinking Abstractly

6.1.1Abstraction

6.2Thinking Procedurally

6.2.1Decomposition

6.3Thinking Logically

6.3.1Pseudocode & Flow Diagrams

7Problem Solving & Programming

7.1Programming Techniques

7.1.1Programming Fundamentals

7.1.2Modularity

7.2Programming Construction

7.2.1Integrated Development Environments

7.2.2Testing

8Algorithms

8.1Algorithms

8.1.1Interpreting, Correcting & Completing Algorithm

8.1.2Sort Algorithms

8.1.3Insertion & Merge Sort

8.1.4Search Algorithms

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