Methods of Error Detection (Cambridge (CIE) O Level Computer Science)

Exam Questions

23 mins7 questions
12 marks

Identify two reasons why errors can occur when using wireless technology to transmit data.

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1
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4 marks

Four 7-bit binary values are transmitted from one computer to another. A parity bit is added to each binary value creating 8-bit binary values. All the binary values are transmitted and received correctly.

Identify whether each 8-bit binary value has been sent using odd or even parity by writing odd or even in the type of parity column.

8-bit binary value

Type of parity

01100100 

 

10010001 

 

00000011 

 

10110010 

 

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23 marks

The contents of three binary registers have been transmitted from one computer to another.

Even parity has been used as an error detection method.

The outcome after transmission is:

No errors have been detected in Register A and Register C.

An error has been detected in Register B.

Complete the parity bit for each register to show the given outcome

Diagram showing three registers (A, B, C) each with 7 binary bits and a separate parity bit. Register A is 0100010, B is 1000000, and C is 1000001.

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34 marks

Victoria is entering data into a computer system. The data will be transmitted to cloud storage.

A check digit is used to check whether data is correct when entered into the system.

Describe how a check digit can be used to make sure the data entered is correct.

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41 mark

Why is it important for computers to check that data is in the expected format?

Provide one example of a format where errors could occur.

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15 marks

Data will be checked using a checksum.

Describe how a checksum can be used to check that data entered into a system has been transmitted correctly

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24 marks

Explain how the Automatic Repeat reQuest (ARQ) protocol ensures data integrity during transmission

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