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Q&A-KCSE Computer Studies Paper 1

State two ways of protecting computers against viruses.

  • 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

A virus is a specific category of malware. 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 a 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 attack 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

Describe what is meant by a MAC address.

  • used to identify a device
  • it is a unique (address)
  • it is a static address // it does not change
  • it is set by the manufacturer
  • the first part is the manufacturer ID/number / identifies the manufacturer
  • the second part is the serial number / ID.

 

 State two components of the CPU

Any two from:

  • Registers
  • Clock
  • CU
  • ALU

State three utility programs associated with the use of a hard drive. Explain the purpose of each the program

  • File handling - Copy/move/delete
  • Anti-virus software - To protect files from attack by a virus
  • Defragmentation - To keep files sensibly arranged on the hard drive
  • Format - To divide the surface of a drive into smaller areas to aid storage

Describe how the database can be recovered from a system failure

  • mirrored hard disk/hot standby/second computer
  • re-run the old master file with the transaction file

451/1

COMPUTER STUDIES

PAPER 1

THEORY

DECEMBER 2021

TIME: 2 HOURS

 

FORM TWO END OF TERM TWO 2O21 EXAM

451/1

COMPUTER STUDIES

PAPER 1

THEORY

TIME: 2½ HOURS

 

INSTRUCTIONS TO CANDIDATES:

  • Write your name and ADMISSION number in the spaces provided above.
  • Write the date of examination and sign in the spaces provided.
  • This paper consists of two sections.
  • Answer all the questions in section A.
  • Choose one topic to answer in section B
  • All answers must be written in the spaces provided in this question paper.

  1. SECTION A
  2.  Answer all questions in this section
  3. What is a computer?                                                                                                            1mks
  4. State three physical components that make up a computer                                                 3mks
  5. State the hardware technological differences between the second generation and third generation computers                                                                                                          2mks
  6. State and explain three characteristics of a computer                                                         3mks
  7. State the functions of the following special memories in a computer                                3mks
  8. Buffers
  9.  
  10. Registers
  11. Cache
  12.  
  13. Define the following as used in data representation in a computer                                  (5mks)
  14. Bit
  15.  
  16.  
  17. Byte
  18.  
  19.  
  20. Nibble
  21.  
  22.  
  23.  
  24. Word
  25.  
  26.  
  27.  
  28. Word-length
  29.  
  30.  
  31. State two reasons why a DVD is superior to a typical compact disk                               (2mks)
  32. State three advantages of flat panel monitors over cathode ray tube monitors                   3mks
  33. Explain the following terms as used in word processing                                                  3mks
  34. Section breaks
  35. Thesaurus
  36. Superscript
  37. State two advantages of  impact printers                                                                             2mks
  38. State the function of the following keys on the computer keyboard                                  3mks
  39. Enter key
  40. Insert key
  41. Delete key
  42. State the technology used by the following secondary devices to store data                      3mks
  43. Magnetic storage devices
  44. Solid state storage devices
  45. Optical storage devices
  46. State three reasons why an operating system is important in a computer                         3mks
  47. A typical computer’s main memory consists of both volatile and non-volatile memory.
  48. i)  Explain what is meant by the term volatile memory                                          (1mark)
  49. ii) What is normally stored in the non-volatile part of a computer’s main memory (1mark)
  50. Explain why having cache memory can improve the performance of the CPU         (2mks)
  51. What is a computer system?                                                                                           (1mk
  52. Give two differences between a solid state drive (SSD) and a hard disk drive (HDD)   2mks
  53. State three categories of software classified according User license agreement              (3mks)
  54. State two disadvantages of Random Access Memory                                                       (1mk)
  55.  
  56.  
  57. a) Explain the functions performed by the following components of a processor   (2 marks)
  58. Control unit

Explain the difference between the sequential and parallel computational models.

Any four of:
Sequential:
Individual instructions are executed one after another
Flow control is accomplished by jump/branch/goto instructions
Results are usually achieved less quickly than parallel processing (do
not award twice)
Parallel:
Individual instructions can be routed to different processors for
simultaneous execution
Results are usually achieved quicker than sequential instruction (do not
award twice)
Requires multi-core processors or multiple microprocessors
Tasks may be split into different parts with each part executed on a
different processor
Results need to be merged back together after completion

Describe two different functions performed by an operating system

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);


 

A company making televisions has introduced robots to replace the human work force.

(a) Describe three effects this would have on the work force

(b) Give two advantages to the company of introducing robots

(c) How could the robots be trained to assemble the televisions?

(d) A whole batch of televisions was produced with some of the parts missing. How could this error have been avoided?

(a) Describe three effects this would have on the work force

  • loss of jobs/unemployment
  • deskilling
  • need to re-train
  • different jobs available/re-skilling
  • no longer need to do hazardous/tedious jobs

(b) Give two advantages to the company of introducing robots

lower work force costs (no salaries to pay)

  • lower environmental costs (less electricity for heating/lighting)
  • higher throughput
  • more consistent product
  • robots don’t need breaks, holidays/work 24/7 etc.
  • robots don’t take industrial action

(c) How could the robots be trained to assemble the televisions?

  • tasks repeated by skilled worker and how each task is done is memorised
  • tasks programmed directly into the computer/robot memor

(d) A whole batch of televisions was produced with some of the parts missing. How could this error have been avoided?

  • if parts missing for a sequence, then a warning should be given and the assembly stopped
  • several quality control stages to spot an error early on
  • program in checks at each stage of assembly so robots can detect a fault immediately

Describe what is meant by a clock speed of 3.8 GHz.

  • The number of FDE cycles run per given time/second
  • the frequency that the clock ‘ticks’
  • 3.8 billion cycles/instructions per second

Explain the functions of the following parts of the CPU

Control Unit; Decodes instruction; Controls the fetching and writing of data;

Arithmetic Logic Unit/ ALU; Executes mathematical instructions;  Executes logical instructions; Compares values held in registers;

 Clock; Controls the number of instructions carried out each second;   allows the CPU to synchronize operations;

List four ways of acquiring software in an organization

  1. Commercial off-the-shelf (COTS) software: Organizations can purchase pre-developed software solutions from commercial vendors. These software products are typically ready-made and designed to fulfill common business needs. Examples include productivity software, customer relationship management (CRM) systems, and accounting software. COTS software can be licensed based on a one-time purchase or a subscription model.

  2. Custom software development: Organizations may choose to develop custom software tailored to their specific requirements. This involves hiring software developers or outsourcing the development work to a third-party vendor. Custom software offers flexibility and can be designed to align with unique business processes and workflows. It allows organizations to have full control over the software's features and functionality.

  3. Open-source software: Open-source software is developed collaboratively and made freely available to the public. Organizations can acquire open-source software without incurring licensing costs. They have the right to use, modify, and distribute the software as per the terms of the open-source license. Open-source software can be an economical option, and it allows organizations to benefit from community-driven development and ongoing improvements.

  4. Software as a Service (SaaS): SaaS refers to software applications that are accessed and used over the internet. Organizations can acquire software on a subscription basis, where the software is hosted and maintained by the vendor. Users access the software through web browsers or dedicated client applications. SaaS eliminates the need for local software installation and offers scalability and accessibility from any location with an internet connection.

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

  • Legend
  • A data series

  • Data Marker

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 that represents a data value

Describe the role of the registers and system clock within the fetch-execute cycle.

  • Registers are small amounts of memory available that hold data fetched from memory or data waiting to be stored in memory. A temporary holding place for the instruction that has been fetched.
  • The system clock purpose is to determine the pace of the cycle, each tick of the clock a part of the fetch-execute cycle occurs. Regulates the timing and speed of a computers systems functions.

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

Give one example of wireless technology

method of transmission e.g

  • blue tooth
  • radio
  • optical
  • satellite
  • infra-red
  • microwave

device e.g.

  • 3G (WAP) mobile phones/mobile phones/cell phone/remote
  • key pad/remote control/keyboard
  • infra-red mouse
  • multimedia mobile handsets/notebooks
  • GPRS (general packet radio service) mobiles
  • WLAN(or WiFi) hotspots sited in public areas - e.g. coffee
  • shops, railway stations, airports, motorway services
  • linked printers
  • PDA's (personal digital assistants)
  • GPS

Describe one difference between system software and application software

  • System software manages the computer hardware/application software
  • application software is for end-user tasks

What precautions would you take in a computer room in case a user complains of backache after long periods of using the computer?

  1. Ergonomic Chair: Ensure that each user has an ergonomic chair that provides proper lumbar support. The chair should be adjustable in terms of height and backrest angle.

  2. Adjustable Desk: Provide adjustable desks or workstations that can accommodate different user heights and allow for proper positioning of the keyboard, mouse, and monitor.

  3. Monitor Placement: Ensure that the computer monitors are positioned at eye level or slightly below to prevent users from straining their necks and shoulders. Consider using monitor stands or adjustable monitor arms for better positioning.

  4. Keyboard and Mouse: Encourage the use of ergonomic keyboards and mice that are designed to minimize strain on the wrists and hands. Provide wrist rests if needed.

  5. Proper Lighting: Ensure that the computer room is well-lit, with appropriate lighting levels to reduce eye strain. Avoid glare on the computer screens by using adjustable blinds or curtains.

  6. Regular Breaks: Encourage users to take regular breaks from prolonged computer use. Suggest the 20-20-20 rule: Every 20 minutes, look away from the screen at an object 20 feet away for at least 20 seconds.

  7. Stretching Exercises: Promote stretching exercises for the neck, shoulders, and back to help alleviate muscle tension and improve blood circulation. Display posters or provide resources on desk stretches and exercises.

  8. Correct Posture: Educate users about proper sitting posture, emphasizing the importance of maintaining a neutral spine position. Provide visual aids or ergonomic training materials to demonstrate the correct posture.

  9. Desk Organization: Encourage users to keep their workstations organized to minimize the need for reaching or straining. This includes keeping frequently used items within easy reach and arranging cables to prevent trip hazards.

  10. Individual Assessments: If the backache issue persists, consider offering individual ergonomic assessments for users. A specialist can evaluate the user's workstation setup and suggest personalized recommendations.

Identify one component common to all computers.

  • Processor