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Q&A-KCSE Computer Studies Paper 1

 Complete the data dictionary below for the Student entity.

  • StudentID: String
  • FirstName: Required 1
  • Year: 2 1
  • Email: Email address containing @ sign 1
  • AccountBalance: Real
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Briefly describe the information Security principles or CIA triads

  • confidentiality - The principle of protection from unauthorized access or disclosure
  • Integrity - the principle of ensuring that unauthorized or undetected changes to data or system configurations do not occur.
  • Availability - the principle of ensuring that data and services remain accessible to authorized users at all times

 

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There are four change-over methods used in the implementation stage of the system development life cycle (SDLC): direct change-over, phased, parallel and pilot.

Direct Change-Over

  • A date is chosen for the shutdown of the old system, then at that time, the old system
    is turned off and the new system is implemented

Phased

  • Parts of the new system are implemented in stages or for a period of time, both the old and the new system are running together until all parts of the system are implemented.
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State the difference between radio waves and microwave transmission

  • Radiowaves are omnidirectional while microwaves propagate in one direction at a time(unidirectional)
  • Radiowaves can be propagated over long distances through sky mode while microwaves require a relay satellite to amplify and retransmit the microwaves signals to the receiver earth station
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Describe the following threats to privacy and confidentiality: Eavesdropping, surveillance and industrial espionage
Eavesdropping refers to tapping or listening into communacation channels to get information. According to study.com, it is defined the unauthorized interception of a conversation, communication or digital transmission in real time study.com
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Describe how ICT is used in marketing

  • ICT provides graphic design tools that allow marketers to create visual content for ads , websites and even social media
  • computers enable marketers to produce video content crucial for modern digital marketing using video editing tools 
  • Computers are used to distribute and analyze online survey polls  that help in understanding customer preferences
  • Social media platforms offer ad placement based on user demographics and interest
  • Online marketing
  • Social media marketing
  • Target marketing
  • Email marketing
  • Blogging
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Explain the following terms

(a) Disk mirroring

(b) Encryption

(c) Backup

(a) Disk mirroring- Data is written on two or more disks simultaneously.

(b) Encryption - Contents are scrambled so they cannot be understood without a decryption key

(c) Backup - A copy of the data is taken and stored in another location

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Differentiate between action query and select query

An action query is used to modify, add, or delete data in a database whereas a select query is used to retrieve data from a database based on specified criteria but does not make any changes to the data.

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State a stage in system development where each of the following activities are carried out    (KCSE 2018)

(a) Identifying technologies that may be used in a proposed system

  • System Analysis/Information gathering/Problem recognition

(b) Identifying the shortcomings of the old system

  • Problem definition

(c) Prepares the software migration plan

  • Implementation stage
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Data integrity in a database can be divided into three categories: referential integrity, domain integrity and entity integrity.

(a)Outline the meaning of each of the following.

(i) Referential integrity

(ii) Entity integrity

(b) Describe how data integrity can improve the process of database management. (2 marks)

(i) Referential integrity

  • Two entities that are related require that a foreign key must have a matching primary key

(ii) Entity integrity

  • Entity integrity specifies that the Primary Keys on every instance of an entity must be kept, must be unique and must have values other than NULL

(b) Describe how data integrity can improve the process of database management. (2 marks)

  • Data integrity is the maintenance of, and the assurance of, data accuracy and consistency over its entire life-cycle and is a critical aspect to the design, implementation, and usage of any system that stores, processes, or retrieves data
  • The overall intent of any data integrity technique is the same: ensure data is recorded exactly as intended (such as a database correctly rejecting mutually exclusive possibilities)
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Define the following

(a) Cookies

(b) Spyware

(c) Phishing

(d)Spam

(e) Pharming

 

 

(a) Cookies

  • Information that a website stores about a user on their hard disk; this enables
    the website to remember details about the user when they next visit the website.

(b) Spyware

  • Program installed on a PC to gather information about the user. It monitors
    every key press and relays the information back to the home base

(c) Phishing

  • Sending an email that claims to be from a legitimate company; the recipient is then directed to a bogus website where their personal details will be collected

(d)Spam

  • Junk/ (unsolicited) electronic mail advertising products and services sent to a general mailing list.

(e) Pharming

  • Malicious code installed on a PC or on a server. This code directs users to a
    a fraudulent website without their knowledge.
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KCSE 2016 COMPUTER STUDIES PAPER MARKING SCHEME

State the function of each of the following keys on the computer keyboard :  (2mks)

Backspace;

  • Deletes characters to the left of the cursor

Insert

  • Add characters at the cursor position
  • Toggles between overtype and insert modes

An organization intends to replace an existing system by carrying out the process in stages .

Name the implementation strategy ;  (1mk)

  • Phased change-over

Give two reasons why the  organization is opting to use the implementation strategy  in (a) above     (2mks)

  • Gives employees time to learn
  • Organizations can revert to the old system in case of failure
  • Reduces resistance by the employees
  • It is easier to find system errors as you are dealing with only one part at a time
  • Accessing parts of the old system is still is possible in case of failure of the new system

 

A manager wishes to replace the current manual system with a computerized one. Describe three areas that must be evaluated to justify the replacement  (6 marks)

  • Technical feasibility
  • Does the current technology suffice
  • Economic feasibility
  • Benefits outweigh costs/ whether the project is cost effective
  • Schedule feasibility
  • Can it be done within the schedule

                                                                      

Headache, back and neck pain may result from the use of computers. State how each of them can be minimized                               (2mks)

  • Proper lighting
  • Regular breaks
  • Use of antiglare
  • Correct position of the screen
  • Ergonomic furniture

Students of a school intended to elect their school Captain by secret ballot.  State three ways in which computers can be used to improve the election process                          (3mks)

  • Registrations of voters
  • Voter identification
  • Actual voting
  • Tallying

Explain why intranet is a more secure way to share files within an organization compared to internet (2mks)

  • Intranet involves the interconnection of computers  within  the organization hence it is easier to monitor the access and sharing of files since the users in an organization can be assigned accounts and passwords which will enable to access files they are authorized to access unlike the internet where many can access what is stored in the organization’s website

List two career opportunities directly associated with computer networking               (2mks)

  • Network administrators
  • Network engineers
  • Network technicians

Distinguish between a formula and a function as used in spreadsheets

  • A formula is a mathematical expression that returns a value
  • A function is an excel inbuilt formula that returns a value given a range of values or arguments

 The C directory of a computer has folders named Form 1, Form 2, Form 3 and Form 4. Each class has students’ folder named according to their admission number.  The student created their own folder for subjects they are studying based on the table below:

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Describe the function of a web browser

Convert the HTML into a webpage which is rendered on the screen

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Give one benefit and one disadvantage of the use of wireless technology.

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
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Define what is meant by a ‘network protocol

  • An agreement / set of rules / standard for how computers should communicate or how data is sent/received/transmitted on a network
  • Example of what could be agreed in the protocol (e.g. speed / error checking / etc.)
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Satellite services are used to provide broadband internet connectivity to regional and remote areas of Kenya. State one advantage and one disadvantage of using satellites for this purpose.

Advantages

  • can cover large areas
  • requires minimal land-based transmission support
  • requires minimal infrastructure to provide internet access
  • minimal impact on the environment or humans.

Disadvantages

  • transmission speeds are not comparable with other forms of transmission
  • data costs are expensive by comparison to other forms of transmission
  • expensive to deliver.
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One facility of a Software Development Environment is to convert source code to machine code.  Name and briefly describe four other facilities commonly found in a Software Development Environment.

  • Editor: this allows a programmer to enter and edit source code
  • Automatic formatting:  Correctly indents code
  • Automatic colour coding:  Changes key words, literals and annotation to different colours
  • Linker: this is a program which allows previously compiled code, from software libraries, to be linked together
  • Loader: this is a program which loads previously compiled code into memory.
  • Debugger: this is a program which helps locate, identify and rectify errors in a program
  • Syntax error detection:  Highlighting syntax errors before code is translated
  • Trace: this is a facility which displays the order in which the lines of a program are executed, and possibly the values of variables as the program is being run
  • Break point: this is a facility which interrupts a program on a specific line of code, allowing the programmer to compare the values of variables against expected values.  The program code can then usually be executed one line at a time.  This is called single-stepping
  • Variable watch: this is a facility which displays the current value of any variable.  The value can be 'watched' as the program code is single-stepped to see the effects of the code on the variable.  Alternatively a variable watch may be set, which will interrupt the program flow if the watched variable reaches a specified value
  • Memory inspector: this is a facility which will display the contents of a section of memory
  • Error diagnostics: these are used when a program fails to compile or to run.  Error messages are displayed to help the programmer diagnose what has gone wrong
  • Emulator: will provide and emulator to run the code/app so no physical device required
  • Context sensitive menu:  SDE suggests available options
  • Statement completion:  SDE will complete a statement such as adding an ‘end if’ to an ‘if’ statement GUI creation:  Allows programmer to create a GUI by dragging and dropping controls (buttons, etc...) onto a form.
  • Publisher: facility to package up and deploy program as an easy to install package
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Give an example of where a PAN could be used

  • connecting wireless headphone to a phone
  • Using a wireless mouse, keyboard etc
  •  
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Explain one drawback to a user if the program is distributed as freeware

The user is not allowed to access the source code so, they cannot tailor the software to their needs and  they cannot fix any bugs in it

The software is still covered by copyright

The user must get the owner’s permission to do anything beyond using it

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COMPUTER STUDIES

PAPER 1

(THEORY)

OCT./NOV. 2005

2 ½ HOURS

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)

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