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Q&A-KCSE Computer Studies Paper 1

List Three file organisation methods in a computer

  • Sequential
  • Random
  • Serial
  • Indexed-sequential

In reference to word processing, define the following terms

Word wrap

Justification

Drop cap

Word wrap - Is a word processing feature in which a word that does not fit in the current line is automatically moved at the start of the next line

Justification - refers to aligning text on both left and right margins

Drop cap - Make the first character of a paragraph occupy more than one line below it

A workshop has a lot of heavy machinery operating throughout the day and requires a cable to connect a workstation to a switch. Which of the following, unshielded twisted pair (UTP) or shielded twisted pair (STP) cable, would be the more suitable? Justify your response.

Shielded twisted pair cable:
A twisted pair cable is made up of four pairs of twisted copper wires, a shielded twisted pair cable applies a shield to each one of the pairs on a cable or to all of the pairs together. This shield can reduce EMI (electromagnetic interference), which would be emitted from heavy machinery. This increased data transmission quality in the workshop. STP can also reduce crosstalk.

Give two examples of each of the following application packages       

a)Spreadsheets                                                                                                                               (2mks)

  • Microsoft Excel
  • Lotus 1-2-3
  • Google Sheets
  • OpenOffice Calc

                                           Any 2 @ 1mk

 

b) Word processors                                                                                                                          (2mks)

  • Microsoft Word
  • Wordpad
  • Corel WordPerfect
  • Lotus Word Pro

 

                                         Any 2 @ 1mk

State and briefly describe three program control structures

Sequence: Sequential execution of a program one line after another

Selection:  Involve the a decision between two or more options e.g  if...then...else

Loops/Repetitions: Used for looping i.e a line of code can be made to execute a given number times before terminating.

What is block operation as used in Microsoft word?

An editing or formatting procedure that is carried out on a selected block of text in a word-processing document.

A formatting or editing operation that is applied to a block of text after selecting. The block of text can be a paragraph, line, word, page or the whole document. It is much easier to apply editing or formatting to a block of text than to apply it to every single character

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

What characterises a phased implementation approach?

  • Phased means that only one part of the system is implemented at a time

(a) Name two pieces of hardware needed to enable video-conferencing to take place using a standard computer system.

(b) State one piece of specialist software needed to carry out video-conferencing.

(a)

webcam
speakers
microphone
broadband modem

(b)

use of CODEC (converts/compresses analogue data into digital data)
echo cancellation s/ware (allows talking in real time/keeps everything in sync)
compression s/ware for video/audio
s/ware to access broadband/networking

Describe three other different categories of malware.

Trojan (horse); a program which misleads the user into thinking it is another
piece of software which, when run, executes another program;
Spyware; a program which records data such as usernames and passwords on
a host system and forwards the information to a third party;
Adware; code embedded or attached to program files which will persistently
show adverts (that attempt to generate revenue);
Worm; code which will run autonomously and replicates itself on a host system;
Ransomware; a program that encrypts user’s data to make it unreadable until
they pay for the key;
Remote Access Tool (RAT); allows access to control and monitor a computer
from a remote network location;
Rootkit; malware that has managed to gain ‘root’ admin privileges;
Bots/Zombies; a program installed on a computer that performs a job for the
remote owner of the bot/zombie such as sending spam or sending web requests
to perform a DOS or attacking a computer system;
Scareware; malware that tells you something is wrong with your system in an
attempt to get you to make a purchase;
Keylogger; a program that monitors/records a user’s keystrokes in order to steal
passwords/confidential details;

Explain the purpose of each of the following features of a spreadsheet chart (KCSE 2021 Computer Studies, Q19 (a))

Legend

  • Legends are a small visual representation of the chart's data series to understand each without confusion.

A data series

  • is a row or column of numbers that are entered in a worksheet and plotted in your chart, such as a list of quarterly business profits
  • A group of related data points or markers that are plotted in charts and graphs

Data Marker

 

 

Explain the purpose of each of the following features of a spreadsheet chart (KCSE 2021, Q19 (a))

Legend

  • Legends are a small visual representation of the chart's data series to understand each without confusion.

A data series

  • is a row or column of numbers that are entered in a worksheet and plotted in your chart, such as a list of quarterly business profits
  • A group of related data points or markers that are plotted in charts and graphs

Data Marker

  • A symbol on the chart that represents a single value in the worksheet.
  • A column, dot, pie slice, or another symbol in the chart representing a data value

https://www.lifewire.com/data-series-data-points-data-labels-3123411

A school has 3000 students sitting final examinations.

Each student sits eight examinations.

Write an algorithm, using pseudocode or a flowchart, which:

inputs the marks for all 8 examinations for each student

outputs for each student the average mark for their 8 examinations

outputs the highest mark overall

highest = -1
for student = 1 to 3000
total = 0
for exam = 1 to 8
input mark
total = total + mark
if mark > highest then highest = mark
next
average = total/8
output average
next
output highest

Python code:

highest = -1
for student in range(1, 3001):
    total = 0
    for exam in range(1, 9):
        mark = int(input("Enter mark: "))
        total += mark
        if mark > highest:
            highest = mark
    average = total / 8
    print("Average:", average)
print("Highest mark:", highest)

VBA Code

Option Explicit

Sub CalculateAverageAndHighest()
    Dim highest As Integer
    Dim total As Integer
    Dim mark As Integer
    Dim average As Double
    
    highest = -1
    
    For student = 1 To 3000
        total = 0
        For exam = 1 To 8
            mark = InputBox("Enter mark:")
            total = total + mark
            If mark > highest Then
                highest = mark
            End If
        Next exam
        average = total / 8
        MsgBox "Average: " & average
    Next student
    
    MsgBox "Highest mark: " & highest
End Sub

 

Describe what is meant by ‘RAID 10’.

  • RAID 10 is a combination of RAID 0 (zero) and RAID 1 (one)

A sound engineer is recording a singer. Describe why the sound must be converted to a digital format before it can be stored on a computer system

  • Computer systems use binary/ones and zeros/voltage on or off;
  • Sound is analogue/continuous;
  • Computers use digital data/discrete values

Define the following terms as used in the internet

HTTPS/HTTP: this is a protocol that is used to send data to web pages across the Internet

Uniform Resource Locator (URL):   a text-based version of a web address

Internet Service provider /ISP  - his is the company that provides a user with a connection to the Internet

browser - Software/application that allows users to view web pages / render HTML -

cookie - a text file (stored by a web browser) that contains data about a user’s browsing habits/details/preferences

Explain how the operating system performs job/process scheduling/management

  • The OS allocates CPU time to each process, and prioritises them in the order of importance

Differentiate between a switch and a hub

A switch forwards data packets directly to the address of the node using point to point transmission method. A hub broadcast the data packets to all computers on the network

KCSE 2016 COMPUTER STUDIES PAPER 1

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 employee
  • 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

State four threats that compromise data integrity and state ways that can be used to minimise these threats

State four threats that compromise data integrity

  • Human error
  • natural disaster
  • data transmission errors
  • software bugs

How threats to data integrity can be minimised:

  • Backup data preferably on an external storage media
  • control access to data by enforcing security measures
  • design user interfaces that minimise chances of invalid data entry
  • using error detection and correction software when transmitting data over the network
  • using devices that directly capture data from the source such as bar code readers, digtal cameras, and optical character readers

 

What is entity integrity?

  • It ensures that each row has a unique and non-null primary key