Error detection

Question 1

Why can errors occur

Answer 1

Due to faulty hardware
Electromagnetic connection

Question 2

3 type of errors

Answer 2

Checksum
Parity
Majority voting

Question 3

Define checksum and check digit

Answer 3

Checksum - String of digits added to end of data to check if data is accurate. Uses an algorithm

Check digit - Checksum that is one digit long

Question 4

How does parity bit system work

Answer 4

Single bit is added to transmission of data. It chooses either a odd or even parity.

Question 5

Issue with parity bit

Answer 5

Only relies on odd/even so if two digits changed then incorrect data may not flag an error

Question 6

How does majority voting work

Answer 6

Sends same bit multiple times. Then goes with most common one.

Question 7

Advantages and disadvantages to checksum

Answer 7

Advantages = Identify more than one type of error
Disadvantage = Needs more processing. Can’t self-repair

Question 8

Advantages and disadvantages to parity bit

Answer 8

Advantages = Simple to implement
Disadvantages = Only detect odd number of errors, can’t self-repair

Question 9

Advantages and disadvantages to Majority voting

Answer 9

Advantages = Can self-repair when more than one error in same bit
Disadvantages = More data has to be sent