(a) Buffer

• temporary storage or memory which compensates for the difference speed of peripherals and the CPU

(b)batch processing

• processing doesn’t start until all data is collected
• JCL (any reference to Job Control Language)
• no need for user interaction
• processed all in one go
• done at “quiet” times
• e.g. billing, payroll, cheque processing

(c) e-commerce

• electronic commerce
• buying and selling products/services using the internet/computer networks

(d) simulation

• studying the behaviour of a system by using a model/mathematical representation
• results can be predicted
• e.g. flight (or other) simulator, modelling hazardous chemical process

(e) Email

• sending messages from one device to another using computer networks/Internet

Windows for example a word processing application and a spreadsheet
 
Menus, for example, allow the user to perform operations or run applications such as right-click to create a new folder  
 
Icons for example a picture of linked computers for networking
 
Pointers(mouse or touchscreen)  for example to select items/trigger events  
 
Shortcuts for example to frequently used applications for example having a shortcut to your mail client on your desktop
 
File navigation for example when searching the hard disc for a file/folder using a browser
 
copying / deleting / moving/sorting/naming/searching of files or folders for example copying of a file from the hard drive to a USB pen drive (File handling)
 
Desktop customisation for example changing the colours and background image
 
Copy and paste for example between applications e.g. copying a graph from a spreadsheet to a word processor
 
Error messages for example provide users with error/warning/help messages for example ‘printer out of paper’ 

1. Application
2. Presentation
3. Session
4. Transport
5. Network
6. Data link
7. Physical

• Portable
• Light
• Faster access speed
• No moving parts
• Efficient power consumption
• Durable
• Small physical size
• Large storage capacity

• virtual memory

• Passive matrix create images by scanning the entire screen whereas active matrix displays are made using thin-film transistors technology(TFT)
• active matrix  display has a higher resolution compared to passive matrix
• Active matrix consume more energy than passive matrix

• Radio waves
• Microwaves
• Infrared waves

Many components that go into computer systems are toxic and dangerous to the environment if released or disposed of inappropriately.
Heavy metals are used in batteries and circuits and these can pollute groundwater or kill animals if left exposed on landfill. Large quantities of plastics are used in systems, which take a long time to break down, some of the plastic will eventually break down into toxins as it degrades.

17. a) i) Explain the term search as used in the Internet.                                            [2]

A web based application that locates items or information from the World Wide Web

ii) Peter intends to download a movie from the Internet. State the three factors that may determine the total time taken to complete the download.                                           [3]

• Size of the video/format
• The bandwidth of the media/speed of network/network traffic
• Type of browser software
• Background activities running in the computer
• Restrictions enforced in the computer/firewall/antivirus
• Speed of the computer/CPU speed
• Size of RAM

b) Wakulima online is an organization that runs a web based system for assisting farmers to obtain market for their produce. State four technological reasons that may cause a farmer not to access the organization’s system.                                                                                  [4]

• Poor network/lack of connection
• Software failure in the system

• Hardware failure
• Lack of access rights
• System overload/hanging
• Lack of skills/disability/illiteracy
• Lack of power supply

c) Explain a situation when each of the following Desktop Publishing program features may be used when creating a publication:

i. Cropping                                                                                                               [2]

Applies to graphics – used to trim/remove/hide some portions in the graphics

ii. Transparency                                                                                                         [2]

Used to make background of a graphic to be clear/visible

d. List two areas where infrared waves are used in data communication.                             [2]

18. a) List four activities of the planning stage of systems development.                             Ignore this question, marks redistributed elsewhere

b) Explain a circumstance when each of the following feasibility studies are carried out during systems development.

i. Technical                                                                                                               [3]

Done to determine whether technology exists to support the proposed solution

ii. Economic                                                                                                              [3]

Done to determine whether the proposed solution is economically viable

iii. Schedule                                                                                                               [3]

Done to determine whether the proposed system can be done within an acceptable time.

c) Table 1 and Table 2 are related tables in a database. Use them to answer the questions that follow.

Table 1

Table 2

i. Identify the appropriate primary key for each table.                    [2]

Table 1 – Dept code, Student Registration No

ii. Explain two benefits of enforcing referential integrity in the database. [4]

• No record can be added in Table 2 if its corresponding record in Table 1 does not exist
• No record in Table 1 can be deleted without first deleting the corresponding record in Table 2
• Reduces data redundancies/ensures integrity
• Prevents deletion of related table

19. a) Describe each of the following validation checks as used in data processing.

i. Preserve check                                                                                                      [2]

Ignore this question, marks redistributed elsewhere

ii. Data type check                                                                                                    [2]

Ensure correct type of data is entered for the field

iii. Check digit                                                                                                           [2]

This is a number added/calculated by the computer to a binary number. The check digit ensures correct transmission of the binary number.

b. Write each of the following abbreviations in full:

i) BCD                                                                                                                                    [1½]

Binary Coded Decimal

ii) EBCD                                                                                                                                 [

This question was thrown out and marks redistributed elsewhere

iii) ASCII                                                                                                                    [1½]

American Standard Code for Information Interchange

c) Using 10-bits binary number system, perform the following decimal operation using two’s complement.                                                                                                                                   [6]

12910 - 12810

+129 = 00 1000 0001

128 = 00 1000 0000

-128 = 11 0111 1111 (ones complement)

                            +1

          11 1000 0000 (Twos complement)

129- 128

     00 1000 0001

+ 11 1000 0000

 100 0000 0001

Hence = 00 0000 00012 or 12 (the overflow bit is ignored)

• To detect and remove errors
• To confirm if the program produces the expected output

Memory management

• Manage the computer’s memory;
• It can control which parts of the memory are being used by which process

Processor management

• Manage the computer’s processor(s)CPU;
• Schedules of which processes are to be executed;

Input/output management

• Manages input/output devices;
• Interacts with/manages/handles the (automatic) installation of device drivers;
•  Handles peripheral device interrupts;
• the computer can communicate with the outside world;
• Control network communication;
• Allow devices to send and receive data;

Managing storage

• Manage secondary storage devices;
• Loading data and programs into the computer’s memory;
• Storage space management (disk quotas);
• To ensure that storage space is allocated fairly and efficiently to specific tasks\users;

Managing security

•  User authentication;
• To make sure that users must prove who they are to access the system;
• Protect against malware;
• Block access to specific vulnerable operations or system areas. For example, software can only be installed with admin access;

Managing applications

• Control access to applications;
• Prevent users or processes from using unauthorised programs // allow users or
• processes to use authorised programs;
• Control application access;
• Prevent/allow an application access to data (or devices);

Cloud computing refers to the delivery of on-demand computing resources over the internet. Instead of relying on a local server or personal computer, cloud computing allows users to access and utilize a wide range of computing services and resources hosted on remote servers.

• Sarah could keep all of her files in the cloud and easily access these with her devices. This way she does not have to keep different version on her desktop and laptop.
• Flexibility she could access the files from other devices such as the library etc.
• Disaster recovery if she accidently dropped or damaged a device – all files would be easy to access.

Both translate source code written in high level programming languages into machine code.
Compiler: Produces a single executable file that is portable between machines
Interpreter: Source code needs a special environment to run
Compiler: Needs to be compiled for a particular architecture
Interpreter: Can run on any architecture that has the translator/interpreter
Complier: Entire source code file is translated at once
Interpreter: Code is translated line by line
Compiler: Provides error report at the end of the compilation
Interpreter: Errors more obvious in the sequence
Compiler: The program source code is not available (so helps protect IP)
Interpreter: Source code is available
Compiler: Only has to be translated once (affecting the speed of execution)
Interpreter: Has to be translated each time, therefore (affecting the speed of execution)
Compiler: Requires two files to be maintained (one for execution and for editing purposes)
Interpreter: Requires only one file to be maintained
 

(i) the potential health hazards of this type of work,

• backstrain due to long periods of immobility
• eye strain due to long periods of staring  at the screen
• RSI- continual use of the same muscle group

(ii) the ways that management can help to overcome the effects of the health hazards.

• Move around regularly
• use ergonomic chair
• use anti-glare screen
• use of wrist pads

State four advantages for using a graphical user interface in loading programs and files

• User friendly
• No need to know command language as commands are executed by clicking on icons
• Allows multitasking as several programs open at the same time therefore easier to switch between applications
• Selecting an item using a mouse is easier and faster than entering commands

Or any other correct response

Advantage @ 1 Mark

Total = 4 X 1 Mark

= 4 Marks

A vehicle assembly company has introduced robots to replace the human workforce.  State two effects this would have on the workforce                

• Unemployment
• Need to retrain
• No longer need to do hazardous or tedious jobs
• Employment of skilled staff who will manipulate the robots

Or any other correct response

Effect @ 1 Mark

Total = 2 X 1 Mark

= 2 Marks

• Patient monitoring
• Used to control medical equipment e.g ultra sound
• medical research and studies
• communication and telemedicine

• Labels
• Values
• Formula
• Functions

SECTION A (40 MKS)

Answer all the questions in this section.

1. a) What is disk formatting?                                                        (1mk)

b) Indicate whether the following devices are used for input or output  (2mks)

i) Plotter

ii)Light pen

iii)Mouse

iv)Visual display unit

2.a)Explain why the following and give one reason why they are not allowed in a computer laboratory. (2mks)

b) For each of the following give one reason why they are not allowed in a computer laboratory.  (2mks)

i) Smoking

ii)Eating foods

3.Distinguish between Real, integer and Character data types as used in programming (3 mks)

4.The cells k3 to K10 of a worksheet contain remarks on student’s performance such as very good, good, fair and fail depending on the average mark.  Write a formula that can be used to count all students who have the remark “very good”      (3mks)

5.a) State the purpose of registers in a computer system               (1mk)

b)Name two multiprogramming operating systems                   (2 mks)

6.a) A series file comprises of records placed in positions 1 to 10.  State the position of the end of file marker.      (1mk)

  b)State the purpose of each of the following: (2mks)

 i)File server software

ii)Communication software

7.a) Name the control structure depicted by the flowchart below.                   (1 mk)

b)Explain the following terms as used in program implementation.      (2mks)

 i)Parallel running

 ii)Direct change over

8. Consider the linear arrays:

 i) AAA (5:50)

 ii)BBB (-5:10)

 iii)CC (18)

Find the number of elements in each array (3mks)

9.Define the term artificial intelligence  (2 mks)

10.Name two types of relationships that can be applied in database design  (2mks)

11.Explain binary Coded Decimal code of data representation (1 mk)

 a)Indenting

 b)Alignment

 c)Word wrap

12.Outline two ways in which a computer can be used in hotels               (2 Marks)

13.a)Explain Binary Coded Decimal code of data representation (1marks)

 b)Write the number 4110 in BCD notation (1 mk)

14.Arrange the following data units in ascending order of size.

   BYTE, FILE, BIT, NIBBlE     (2mks)

15.State two health issues that may result from prolonged use of computers     (2 mks)

SECTION B (60 MARKS)

16. a) State the stage of program development in which  (4 mk)

i) A flowchart would be drawn

 ii)The programmer would check whether the program does as required

 iii)The user guide would be written

iv)The requirements specifications would be written.

b)State the output of the following flow chart segment                  (1mk)

c) i)Draw a flowchart to compute the combined resistance ® of two resistors R1 and R2 in parallel using the formula;

                      (5mks)

ii)Write a program using Pascal or C languages for the flowchart in C (i) above. (5 ½ mks)

17. a)List three paragraph formatting activities in word processing  (3mks)

 b)Differentiate between bolding and highlighting text (2mks)

c) The following information shows the income and expenditure for “bebayote “ matatu for five days.  The income from Monday to Friday was Kshs. 4,000, 9,000, 10, 000, 15,000 and 12,000 respectively while the expenditure for the same period was Kshs.  2,000, 3,000, 7,000, 5,000 and 6,000 respectively

i)Draw a spreadsheet that would contain the information.  Indicate the rows as 1, 2, 3 …. And the columns as a, B, C    (4mks)

ii)State the expression that would be used to obtain:

 I Monday’s profit  (2mks)

 II Total income (2mks)

III)Highest expenditure (2mks)

18.a) Subtract 0112  from 10012 (1mk)

 b)Using two’s compliment, subtract 7 from 4 and give the answer in decimal notation (4mks)

c) Convert

i) 91B16  to octal    (3mks)

ii) 3768   to hexadecimal   (3mks)

iii) 9.62510 to binary  (4 mks)

19.a) Explain what the following DOS commands will do when executed.

    i)  A: \copy *.* B:    (2 mks)

   ii)   C: \> ERASE*. DOC   (2mks)

  iii)   b: \> Md EXAMS  (2mks)

 b)  i)  With the aid of a diagram, explain hierarchical (tree) network topology   (3mks)

  ii)List two advantages and two disadvantage of hierarchical network topology.  (4 mks)

   Advantages:-

   Disadvantages:

20. a)Name and explain the function of the keyboard keys represented by the following symbols.

  b) Simulation is one of the application areas of computers        

  i) What is meant by the term simulation      (1mk)

  ii)Name two application areas of simulation   (2 mks)

 iii) State three advantages of computer based simulation (3 mks)

 c) Explain three ways in which computers have impacted education (3mks)

• Is an integration of sound, text, graphics, and video to convey information

• she had actually described verification
• data could be incorrect, therefore same incorrect data typed in twice
• accept description of validation process e.g. range check