GCSE Computing/Representation of Data in Computer Systems

Units

 * (a) Define the terms
 * bit,
 * nibble,
 * byte,
 * kilobyte,
 * megabyte,
 * gigabyte,
 * terabyte.

(b) understand that data needs to be converted into a binary format to be processed by a computer.


 * (c) Convert positive denary whole numbers (0-255) into 8-bit binary numbers and vice versa
 * (d) Add two 8-bit binary integers and explain overflow errors which may occur
 * (e) convert positive denary whole numbers (0-255) into 2-digit hexadecimal numbers and vice versa
 * (f) convert between binary and hexadecimal equivalents of the same number
 * (g) explain the use of hexadecimal numbers to represent binary numbers.

Character
Candidates should be able to:
 * (h) explain the use of binary codes to represent characters
 * (i) explain the term character set
 * (j) describe with examples (for example ASCII and Unicode) the relationship between the number of bits per character in a character set and the number of characters which can be represented.

Images
Candidates should be able to:
 * (k) explain the representation of an image as a series of pixels represented in binary
 * (l) explain the need for metadata to be included in the file such as height, width and colour depth
 * (m) discuss the effect of colour depth and resolution on the size of an image file.

Sound
Candidates should be able to: the quality of its playback.
 * (n) explain how sound can be sampled and stored in digital form
 * (o) explain how sampling intervals and other considerations affect the size of a sound file and

Instructions
(p) explain how instructions are coded as bit patterns (q) explain how the computer distinguishes between instructions and data