Data Representation

Question 1

Describe how negative numbers are represented in twos compliment

Answer 1

The binary of the positive equivalent is inverted and 1 is added to the Least Significant Byte (LSB)

Question 2

Compare the ways in which characters are represented in ASCII and Unicode

Answer 2

ASCII- uses 7 bits, can represent 128 characters. The 8th bit can be used for error checking.

Unicode- Is a sixteen bit extension of ASCII, can represent 65536 characters

Comparison- unicode can represent far more characters than ASCII allowing for the interchange, processing and display of the majority of the worlds language, rather than just one. ASCII uses fewer bits than unicode which could result in faster processing

Question 3

Explain how both positive and negative numbers can be represented in two’s compliment

Answer 3

MSB is used as a sign bit, MSB is 0 for a positive number and is a 1 for a negative number. For a positive number place values used, for negative it is stored as twos compliment, which is got by inverting the bits and adding 1 to LSB

Question 4

Explain what is meant by a character set.

Answer 4

The range of characters that can be represented. Each character has unique binary code. These include letters and digits.

Question 5

How many characters can be represented with ASCII?

Answer 5

128

Question 6

ASCII uses 7 bits, suggest a use for the 8th

Answer 6

Can be used for error checking as a parity bit, can be used to represent additional characters.

Question 7

What does TB mean and how many gigabytes does it contain/

Answer 7

Terabyte, 1024

Question 8

Discuss the benefit of using Unicode over ASCII

Answer 8

More characters can be represented, unicode uses 16 bits, allows characters from the majority of the worlds languages to be represented.