• It refers to a computer that controls other computers in a network and monitors user's access to the shared resources.

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)

– fact finding
– feasibility study
– analysis
– design
– testing
– documentation
– implementation/changeover/installation
– evaluation
– maintenance

2.1.1 Explain the concept of open source in the context of FOSS. (2)

• Is a software whose source available and user can modify and redistribute

Give ONE example of a free operating system the company could install on a laptop. (1)

• Linux
• FreeBSD
• ReactOS
• Android
• ChromeOS
• OpenSolaris

2.1.3 State TWO disadvantages of using free open-source software.

• Lack of support
• Security risks
• Compatibility issues
• Hidden costs

Taking a four-digit 0  binary number i.e (0000)2

In ones complement this is  1111

In twos complement this becomes 1111+1= 0000

So, It is clear that 0 and negative zero is the same in twos complement while in ones complement they are two different values

• College authorities are the experts in the problem
• A system Analyst is an expert with computers
• The two need to pool resources to come up with a clear definition
• Agree on the outcomes so that when the system is , there are a set of criteria to judge it by

Input : An algorithm can take 0 or more inputs well defined outputs

Finiteness: an algorithm must terminate in finite time and after finite number of steps. 

Definiteness : an algorithm must be clear and unambiguous. Each and every step of an algorithm must be clear and precise and it must have only one meaning

Feasibility: should be feasible with the available resources

Output : must produce at least one well defined output

Independent : should have a step-by-step directions which is independent of any programming language

Correctness: should solve the problem it is designed to solve

Efficiency: must take the shortest time possible to run and should require the least memory space. It should use a minimum number of computation steps and memory to produce the desired  output. takes little time and memory to run

Generality: should not be limited to a specific case. It should work for all the valid inputs. works for many possible inputs

Effectiveness : should statements that are relevant to the problem. Every step must be basic and essential. 

Advantages

• Sharing of software and data files
• Sharing of hardware, e.g. printers
• Communication

Disadvantages

• Security of files is more of a problem

• The preparation of a system proposal which lists the problem definition, objectives of the study, terms of reference of study, constraints, and expected benefits of the new system, in light of the user requirements

(a)Explain why programmers prefer to represent instruction in hexadecimal rather than in binary

• A larger number of values can be represented using fewer characters.
• the shorter length and more characters make the pattern easier to read and understand
• recognisable character codes can be used for debugging

(b) Give two other uses of hexadecimal

• HMTL color codes representing RGB spectrum in the web development
• representation of MAC and IP addresses allowing a larger combination of unique addresses

• do not allow outside floppy disks/CD’s/DVD’s
• use disk free work stations
• download/install and use anti virus software
• scan hard disks regularly
• update the anti virus program regularly
• do not open file attachments from unknown sources/download
• doubtful software from the Internet
• do not use files that come from unknown sources
• buy original software/do not buy pirated software
• use firewalls

• The user can access the source code  so, they can tailor the software to their needs and they can fix any bugs in it
• the source code could be studied for educational purposes
• The user can redistribute the software/program  but this must be done under the same terms as the original software

SECTION A (40 MARKS)

Answer all the questions in this section

1.Computer systems are built from three types of physical components: processors,memories and 1/O devices.

  a) State two tasks of a processor                                                            (2 mks)

  b)State function of 1/O devices                                                               (1 mk)

2. Threats to the safety of computer systems take many forms such as:  white-collar crime, natural disasters, vandalism and carelessness.Give on way as to how each of these forms of threats can be controlled.    2 mks)

3.a) Explain the term nibbles as used in data representation in computers

   b)Perform the following binary arithmetic giving the answers in decimal notation.     (3 mks)

       i)1110.01111 + 11010001 .011

        ii) 1001011.011 - 111.111

     4  a)  Distinguish between machine and assembly language           (2mks)

         b) State the type of translator necessary for a program written in:         (2mks)

            i) High level language

           ii)Assembly language                                                    

5. Briefly explain the purpose of the following types of program documentation: (3mks)

    a)  User manual

     b) Reference guide

     c) Quick reference guide

6. State any two features of a user-friendly program.      (2mks)

7 a) Distinguish between labels and formulae with respect to spreadsheets (2mks)

   b) Consider the entries in the cells below.

State the value displayed in cell C13                                      (2 mks)

8.List three differences between wide area Networks (WAN) and Local Area Networks (LAN)      (3mks)

9. Study the flowchart segment below and state the last value printed from the flowchart.         (2 mks)

10.  a) What is an expert system                                                        (1mk)

      b)State any two components of an expert system                     (2mks)

11. give two reasons why optical disks are better storage media compared to floppy diskettes  (2mks)

12.What are the Dos commands used for the following?                       (2mks)

            a) Changing directories

            b) Viewing directories

           c)  Renaming directories

            d) Deleting a directory

13. Distinguish between copying and moving text                                  (2mks)

14. a) Name two methods of paper orientation                                (1mk)

     b)Name two keys used to delete text in a document   (1 mk)

15.Name two features a Database package                                             (2mks)

SECTION B (60 MKS)

Answer question and any other three questions from this section

16.       Study the flowchart below and answer the questions that follow.

 a)Write a high-level language program for the above flowchart (7mks)

 b)List the outputs of the flowchart above                                 (5 mks)

 c) Modify the flowchart so that it adds up all its outputs and displays the sum obtained  (3mks)

17. A computer specification has the following details:

•  Pentium II
• 1.44 MB floppy disk drive
• 20 GB hard disk
• Full multimedia
• 17” SVGA monitor
• Pre-installed operating system
• Pre-installed office suite

     a)  What is meant by

       i)  1.44 MB floppy disk drive?

       ii)20 GB hard disk?

      iii) 17” SVGA monitor

     b) Which operating system might be pre-installed in this computer and why?         (2mks)

     c) List three multimedia components                                          (3 mks)

      d) i)  what is meant by computer aided manufacture?        (2 mks)

          ii)  Give two examples of computer aided design software.       (2mks)

18. a)Give three examples of network software                                          (3mks)

     b)List any three items that may be referred to as data terminal equipment in a network     (3 mks)

     c)Briefly explain the following terms as used in networking   (4mks)

      i) Remote communication

      ii)Distributed processing

      d) State three advantages and two disadvantages of mesh network topology. (5mks)

19. a)  a company has decided to computerize their operations.  They have decided to purchase package instead of developing their own programs.  Give three advantages and two disadvantages of this approach. 5mks)

      b) i) explain why a value such as 611233444555 may be displayed as ######### When typed in a cell of a spreadsheet (2mks)

       ii)  How can the problem in b (i) above be corrected?      (2mks)

      c) With reasons, briefly describe the most appropriate type of printer output device for the output of:  (6mks)

      i) Customer invoices on multi-part stationery

     ii) Letters to customers

     iii)Detailed engineering designs

20. a)  Distinguish between the following pair of terms                                (6mks)

      i) Data verification and data validation

      ii)Data encryption and passwords

• To get the latest features
• To update security features

• novice can use the system right away
• user-friendly/easy to select
• click on icons/picture to select
• easier to input/words are replaced with icons
• no need to know command language to use the system/remember
• command language
• selecting item using mouse is faster than entering commands
• avoids typing errors
• no need to type
• no need to remember commands
• no need know the different commands for the different software
• multitasking (several programs open at the same time therefore easier
• /faster to switch
• easier/faster switching between files, folders etc.

(i) Crop - used when handling a graphic and there is a need to remove some of the portions in the graphic

(ii)Transparency - used when there is a need to make background of a graphic visible

• Authenticity
• Users' needs
• Availability of documentation
• Cost
• Compatibility
• Upgradability
• Portability

May not have space for cables to be installed

Employees and visitors can move around the building without disconnecting

Adding new users just means giving out the SSID and password

Advantages

• no wires
• fast/high-speed wireless Internet access
• WLAN is faster than a modem or mobile
• WLAN for working at home one day a week/teleworkers
• see internet content away on the move
• create and send multimedia messages to mobiles or e-mail
• picture messaging - send photos/pictures text/sound/recorded
• greetings from mobiles to mobiles/PCs
• instant transmission - no busy signals/no searching for phone jacks
• download e-mail and file attachments on mobile
• watch live webcast on mobile/hotspot
• listen to streaming video on mobile/hotspot
• news/weather/sport/games while on the move
• access information from mobile anytime
• send/receive/delete e-mail while on the move
• wireless Inbox on mobile - to contacts and calendar
• view business appointments while out of the office on mobile
• send corporate e-mail while out of the office - even behind a firewall on mobile
• wireless internet connection from chat rooms for discussions with colleagues while on the move
• give visual demonstrations from mobile and colleagues watch back at the office

 disadvantages e.g.

• WLAN speeds are slower than Net access at work/narrow band width
• any one within the WLAN nodes range with an appropriate device can use your WLAN and broad band link
• any one who walks past your house or WLAN linked into a corporate system can access sensitive information or credit card details
• 3G phones not compatible with 2G phones
• Blue tooth - has limited range
• blocked signal/distorted signal/weak signal/lag
• health problems from microwaves

• Serial is the transmission of data one bit at a time/through one wire
• Parallel is the transmission of data more than one bit at a time/many wires
• Simplex is the transmission of data in one direction only
• Duplex is the transmission of data in both directions simultaneously