Data Representation ASCII
What is ASCII • A – American • S – Standard • C – Code for • I – Information • I – Interchange
Character Set • A character set is all the letters, numbers and symbols on a keyboard. • ASCII is a character set. The character set will vary between countries e.g. if any of you study French you will know that some their characters are different, so they have a different character set. • It is possible to change the character set used on a desk top computer.
How is ASCII Stored • ASCII is stored in bits and only 7 bits are required to store the code, but because we usually deal with groups of 8 (a byte) so an additional zero is added to the start of the code.
ASCII codes ASCII assigns every character in your character set with a unique code.
Control Character • Most ACSII characters are either displayed on screen or can be printed on a printer. E.g. A, 2 • Control characters include keys such as RETURN, TAB and DELETE. These are action buttons, that don’t show on screen.
Using 7 bits it is possible to store 27 = 2x2x2x2x2x2x2 = 128 • Different characters in ASCII, However the English language requires fewer than 128 characters.
Written Task Exercise 2 (all)