Computer Science
Why is binary used in Computer Science
As we either have the presence or absence of an electroical volt
Define a character set
A complete set of characters and their unique number codes that is recognised by the computer hardware & software
What is the modern version of ASCII called. How many bits per character is used in it and what is it used for
Extended ASCII, uses 8 bits per character and used to represent characters like letters with accents
Give 2 features of ASCII
- Uses 7 bits per character
- The first 32 character are known as controlm characters
Why was Unicode created
To standardise the encoding of characters from all languages
Give 2 features of unicode
- Can apply a variable length encoding of either 16/32 bits
- The first 128 characters are the same as ASCII
Give a disadvantage of using Unicode
- It uses 4 bytes per character & takes up 4 times the amount of space compared to ASCII
How many bits is the Unicode character set
24
Give 2 ways of representing negative numbers
- Sign and magnitude
- Two's complement
Why is it better to write negative numbers as 2s complement rather than sign and magnitude
- It's easier to do arithmetic calculations with 2s complement