1.4.1 Data Types

Question 1

What is a logical shift?

Answer 1

• a shift performed on a binary numbers
• logical shift left : multiplication
• logical shift right : division
• n= number of places shifted, has the effect of multiplying or dividing by 2^n

Question 2

Masks

Answer 2

Can be applied to binary numbers by combining them with logic gates

Question 3

Bits and bytes

Answer 3

• a bit is a binary digit (can be 1 or 0)
  -which is the fundamental unit of information
• 1 and 0 are used to represent 2 electrical states on and off
• 8 bits = 1 byte
• 4 bits = 1 nibble

Question 4

Character set

Answer 4

• A published collection of codes paired with corresponding characters.
• Enables computers to represent text using binary code.
• Two main character sets are Unicode and ASCII.

Question 5

ASCII (American Standard Code for information interchange)

Answer 5

• a character set used to map binary values to characters [1]
• uses 7 bits to encode each character [1]
• can represent 128 distinct characters
• is used to represent characters in the English language

Question 6

ASCII benefits

Answer 6

Uses a lot less storage space than Unicode

Question 7

ASCII drawbacks

Answer 7

• it has a limited number of characters/ is limited to 128 characters
• it can’t represent multilingual characters/text
• it does not include special characters like emojis

Question 8

Unicode

Answer 8

• a character set which is used to map binary values to characters [1]
• uses up to 32 bits to encode each character [1]
• it supports a very large number of characters [1]
• used to represent characters across the world

Question 9

Unicode benefits

Answer 9

• it can represent more characters than ascii
• it can represent special character such as emojis
• it can represent multilingual text

Question 10

Unicode drawbacks

Answer 10

It uses a lot more storage space than ASCII

Question 11

Trade off between accuracy and range

Answer 11

• larger mantissa increases accuracy [1]
• smaller exponent decreases range [1]

Question 12

Explain how codes are used to represent a Character set

Answer 12

• each symbol has a unique binary code [1]
• e.g ascii uses 7 bits per character