ASCII / UNICODE Flashcards
What is a character set?
Give examples
A collection of characters and the binary code used to represent them
ASCII, Unicode
How many bits does standard ASCII use to represent a character?
7 bits are used to represent a character
How many characters can be represented in standard ASCII?
2^7 = 128 different characters
What is the range of characters that can be represented in standard ASCII?
0 - 127
When is an 8th bit sometimes added to standard ASCII ?
It’s sometimes used as a parity bit for error checking during transmission
How many bits does extended ASCII use to represent a character?
8 bits are used to represent a character
How many characters can be represented in extended ASCII?
2^8 = 256 different characters
What is the range of characters that can be represented in extended ASCII?
0-255
How many coding standards does Unicode support?
Name them.
Unicode supports 3 standards
UTF-8 , UTF-16, UTF-32
What advantage is gained from using Unicode as the character set over ASCII?
ASCII can only represent a fixed amount of characters due to how many bits it uses so it limits how many characters it can represent whereas Unicode uses more bits so can represent a greater amount of characters, such as characters used in different languages/alphabets
What is a character code?
A binary pattern equivalent of a character
What is a disadvantage of using Unicode?
It uses more bytes per character so uses more storage space per character
What’s an advantage of using the stored program concept?
It allows one computer to run several different programs
