Marking Scheme · Computing Form 4 Track 3 Half Yearly Exams 2014 Page 1 HALF-YEARLY EXAMINATIONS - FEBRUARY 2014 Computing Form 4 Track 3 (TIME: 1 hr and 30 mins) Marking Scheme

Computing Form 4 Track 3 Half Yearly Exams 2014 Page 1

HALF-YEARLY EXAMINATIONS - FEBRUARY 2014

Computing Form 4 Track 3

(TIME: 1 hr and 30 mins)

Marking Scheme

Computing Form 4 Track 3 Half Yearly Exams 2014 Page 2

Section A – Answer ALL questions. Each question carries 5 marks.

1. An 8-bit register contains the binary number 11010.

a. What is a register? [2]

A register is a special high-speed storage area [1]

that can hold data temporarily (for a short time). [1]

b. What may be done to the bits in the register (11010) to double

(multiply by 2) the value of the number?

[1]

Arithmetic Shift Left

c. Show how the result of part (b) is stored in the 8-bit register. [1]

00110100

d. Convert the result of part (b) to decimal. [1]

52

2. The following is a list of characteristics of tailor-made and off-the-shelf

software. For each characteristic, tick the appropriate box.

[5]

Off-the-

Shelf

Tailor-

made

a. Generally a more expensive option. √

b. More likely to find user support for the

software on the Internet.

√

c. Is created to meet the detailed requirements of

a specific customer.

√

d. Has features designed to suit the most

common needs of a large number of people.

√

e. One can’t get a software review beforehand as

no other users would have used this software.

√

Computing Form 4 Track 3 Half Yearly Exams 2014 Page 3

3. The Two’s Complement system is the most common method of

representing signed integers on computers.

a. Convert the following signed Decimal numbers into 8-bit Binary

numbers using Two’s Complement representation:

[3]

i. 79 ii. -40

01001111 11011000

b. Work out the following by using the answers in part (a):

79 – 40

[2]

00100111

4. Registers are of a fixed size.

a. What type of error occurs if the number to be stored requires more

bits than the size of the register?

[1]

Overflow error

b. What is the range of unsigned integers that can be stored in an 8-bit

register? (Give your answer in decimal)

[2]

0 – 255 Accept Also: 0 – (28-1)

Computing Form 4 Track 3 Half Yearly Exams 2014 Page 4

c. What is the range of two’s complement numbers that can be stored

in an 8-bit register? (Give your answer in decimal)

[2]

-128 to +127 Accept Also: – (28-1

) to (28-1

- 1)

5. There are two types of software: System Software and Application

Software.

a. What do you understand by the term software? [1]

Software consists of all the programs which run on a computer

b. What is the difference between System Software and Application

Software?

[2]

System: programs which control the hardware

Application: programs which the user can use to perform particular

tasks or to solve particular problems

c. Give an example of each type of software (apart from Operating

System).

[2]

System Software: Any relevant example (except O.S.)

Application Software: Any relevant example

6. An Operating System is considered as System software.

a. Mention ONE Operating system you are familiar with. [1]

Any relevant example

b. What should be installed first, System or Application software? [1]

System software

Computing Form 4 Track 3 Half Yearly Exams 2014 Page 5

c. Mention TWO things that happen during the installation process. [2]

program files might be uncompressed / program files are put into their

correct sub-directories / the system is configured for usage of the new

software

d. Mention ONE customization that can be performed by the user

when installing software.

[1]

changing installation folder / installing only some components of

software

7. a. Give a number to each of the following Systems Life Cycle stages in

the right order. The 1st step has been marked already.

[3]

6 Control and Review

4 Programming and Documentation

7 Maintenance

3 System Design

1 Project Selection and Feasibility Study

5 Implementation

2 Analysis of Current System

b. One of the steps of the Systems Life Cycle is Feasibility Study. Why

is Feasibility Study very essential?

[2]

It is essential because the feasibility study helps in understanding the

problem and in determining whether it is worth proceeding or not.

8. a. What is the main difference between Technical and User

Documentation?

[2]

Technical: has to be helpful to enable a programmer to modify the

Computing Form 4 Track 3 Half Yearly Exams 2014 Page 6

program as necessary

User: must be written in a way that a non-specialist user can use the

program easily

b. Mention ONE essential feature (or section) that one expects to find in

each of these 3 types of documentation:

[3]

Technical: Any relevant answer

User: Any relevant answer

Program: Any relevant answer

9. After a program is written, it must be tested.

a. What do you understand by test data? [1]

Valid and invalid data used to check if an actual output of a software

corresponds with the expected output

b. What is a Dry Run? [1]

It involves going through each stage of the program and writing what

is happening in the program’s variables

c. Distinguish between the three types of programming errors and for

each type of error, write down ONE typical example of such error.

[3]

Syntax Error: It is an error in the use of reserved words and

structures of the programming language

Example: Any relevant example

Logical Error: It is an error in the logic of the program

Example: Any relevant example

Computing Form 4 Track 3 Half Yearly Exams 2014 Page 7

Runtime Error: It is an error that happens while the program is

running

Example: Any relevant example

10. Two important steps in the System Life Cycle are Project Selection and

Maintenance.

a. Mention FOUR methods that a System Analyst can use to

understand and analyse the present old system.

[2]

Method 1: Interviewing persons who use the system

Method 2: Examining current documents and output of the system

Method 3: Sending out questionnaires and analysing the responses

Method 4: Observation of current procedures

b. There are THREE types of maintenance. Explain in detail each one

of them.

[3]

Perfective:

Although the system runs satisfactorily, this maintenance is done for

further improvement

Adaptive:

This maintenance is done to adapt to changing needs within a

company

Corrective:

This maintenance is done to solve problems that frequently surface

after a system has been in use for a short time

Computing Form 4 Track 3 Half Yearly Exams 2014 Page 8

11. Fill in with either (T) True or (F) False [5]

a. \n is used to start a new line T

b. An attribute of type byte stores numbers larger than an

attribute of type int

F

c. Java Keywords can be used as variable names. F

d. The following is a valid attribute declaration: char ch; T

e. A class must always have a main method F

12. Change-over is an important stage in the Systems Life Cycle.

a. Mention 4 Change-over methods. [2]

Direct / Parallel / Staggered / Pilot-run

b. Explain in detail ONE of the Change-over methods in part

(a);

[2]

Any relevant answer

c. Which is the best Change-over method which can be used

for a small shop? Give a reason.

[1]

Direct Change-over because few persons are involved and

the process is very short.

Computing Form 4 Track 3 Half Yearly Exams 2014 Page 9

Section B – Answer BOTH questions. Each question carries 20 marks.

12. This question is about Areas of Computer Applications.

a. What do the following acronyms stand for? [5]

EFT Electronic Funds Transfer

CAD Computer Aided Design

CAM Computer Aided Manufacturing

GPS Global Positioning System

CAL Computer Aided Learning

b. Explain CAL in detail. [2]

The use of technology to assist in the process of learning

c. Give TWO situations where CAL may be adopted. [2]

Situation 1: Teleconferencing in inter-school projects

Situation 2: Virtual Learning Environment ex. Fronter

d. What is e-commerce? [2]

The buying and selling of goods and services on the Internet

e. How is EFT related to e-commerce? [1]

Through EFT, a customer can buy products or services electronically

by using credit cards, debit cards, etc.

f. Mention TWO advantages of using CAD when compared to the

traditional ‘pencil and drawing-board’ method?

[2]

1st advantage: precise drawings

2nd

advantage: designs can be re-edited

Computing Form 4 Track 3 Half Yearly Exams 2014 Page 10

g. Choose THREE of the following topics and write how they affect

people in today’s modern technological lifestyles.

[6]

GPS ATM CAM

Simulation e-Government

Topic 1: Accept any relevant answers

Topic 2: Accept any relevant answers

Topic 3: Accept any relevant answers

Computing Form 4 Track 3 Half Yearly Exams 2014 Page 11

13. Answer the following questions with regards to the program shown below.

a. What is the class name? AddNums [1]

b. What are the variable (attribute) names of the two numbers? [2]

num1 num2

c. Mention another variable (attribute) type which can be used with

numbers.

[1]

byte / short / long / float / double

d. Which line is adding the two variables (attributes)? 8 [1]

e. In which variable (attribute) is the total of the two numbers stored? [1]

sum

Computing Form 4 Track 3 Half Yearly Exams 2014 Page 12

f. Which lines initialize a variable (attribute)? 5 and 6 [1]

g. Which line outputs the result? 9 [1]

h. Rewrite lines 8 and 9 so that it works out and outputs the

multiplication of num1 and num2.

[4]

int mult = num1 * num2;

System.out.println(mult);

i. On the next page there is an incomplete java class named Triangle.

i. Declare TWO more variables (attributes) b and area.

ii. Ask the user to input side b of the triangle in the method

inputDetails() and read this value.

iii. Complete the method printArea() to work out the area of the

triangle and print the answer on screen.

[2]

[2]

[4]

import java.util.Scanner; public class Triangle{

double a;

double b;

double area;

public void inputDetails(){

Scanner input = new Scanner(System.in);

System.out.print(“Enter side a: “);

a = input.nextDouble();

System.out.print(“Enter side b: “);

b = input.nextDouble();

}

public void findArea(){

area = 0.5* a * b ;

System.out.print(“Area is “+area);

}

}