iGCSE Computer Science - Distance Learning

Course Information
Data Representation (Number Systems)
Text, Sound, & Images
Data Storage & Compression
Tutor Marked Assignment 1
Communication & Internet Technologies
Tutor Marked Assignment 2
Hardware & Software
Tutor Marked Assignment 3
Computer Software
Tutor Marked Assignment 4
Data Security
Tutor Marked Assignment 5
Ethics & AI
Tutor Marked Assignment 6
Algorithm Design & Problem Solving
Tutor Marked Assignment 7
Programming (Python)
Tutor Marked Assignment 8 (Programming)
Databases
Mock Exams

Representing Digital Text (2023 Specification Only)

New 2023 Syllabus Only

We already know that computers hold data using binary, so representing characters requires the computer to convert from alphanumeric (letters & numbers as text) into binary.

So how do you convert a letter into binary? The simple answer is that you can’t. Instead, each character is assigned a number value which is stored in a table known as a Character Set.

There are two main character sets, both of which are discussed at GCSE. The first of these is ASCII (as-key), American Standard Code for Information Interchange.

If you haven’t completed the KS3 Computing course, now is a great time to watch the lesson on representing data. If you have completed the course, use this as a reminder!

One of the questions often asked in an exam is how many characters can ASCII represent. We can calculate this by knowing that it uses 7 bits of binary data to represent each character:

The maximum binary number with 7 bits is: 1111111

1111111 = 127

127 + 1 = 128

Why the +1? Because 0 is a number!

With 16 bits, the capacity was enough to represent all possible alphabets and still have enough room to save emojis 