Characters: Computer Science OCR: GCSE (9:1)

ASCII

Character set using 7 bits to represent each character, giving 128 unique characters

Character Set

A code that pairs each character from the alphabet with a unique binary number so we can store text in a computer, examples are ASCII and Unicode

Encoding

The process of converting data into a binary code so that a computer can process it

Unicode

Versatile character set using up to 32 bits so it can represent many more characters. The first 128 are the same as ASCII.

7

Number of bits in an ASCII code

32

Maximum number of bits in a Unicode representation

128

Total number of possible values in the ASCII character set

4

Number of bytes in a 32-bit Unicode value

File size

Using Unicode makes this bigger, because each character takes up more space

B

"A" has the ASCII code 65. What letter has the code 66?

Chinese

There are thousands of characters in the ___________ alphabet. ASCII is not a suitable character set for the language because it has too few bits to represent all the possible values.

English

ASCII is suitable for encoding the ___________ language because after counting all upper and lower case letters and punctuation, there are fewer than 128 characters

101 0001

The letter "P" has the ASCII code 101 0000. What is the binary code for "Q" in the ASCII character set?

116

Lower case letters have an ASCII value 32 places higher than their upper case equivalent. "T" is 84, so what is "t"?

010 0000

The space symbol is stored as decimal value 32 in the ASCII character set. What is this in binary?

011 0101

The number zero, when stored as a character using the ASCII character set, is given the code 48. The numbers 1 to 9 follow consecutively. So what is the binary code for "5"?