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Q&A-KCSE Computer Studies Paper 1

What are computer networks?
A set of connected computers and other devices which share resources such as software, internet connection,printers etc
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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.

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Give one advantage of a star network when compared to a ring network.

if one station/cable fails, others are not affected
easier to identify faults when using star topologies
it is easier to expand this type of network
performance doesn’t deteriorate under load

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Explain one reason why a computer needs to be connected to a stable power source

System Stability: Computers require a consistent and stable power supply to function properly. Fluctuations or interruptions in the power source can cause various issues that can disrupt the computer's operation or lead to hardware damage.

a. Data Loss: Sudden power outages or voltage fluctuations can cause the computer to shut down abruptly, resulting in data loss if unsaved work is not properly stored. This can be particularly problematic when working on critical tasks or handling important files.

b. Hardware Damage: Power surges or inconsistent power supply can damage the computer's internal components, including the motherboard, CPU, memory, and storage devices. These damages can result in system instability, reduced performance, or even complete hardware failure.

c. Operating System Corruption: Abrupt power loss or inconsistent power supply can corrupt the operating system files, leading to system crashes, error messages, and instability. This may require system repairs or reinstallation of the operating system.

d. Component Lifespan: Inconsistent power supply can put unnecessary stress on computer components, shortening their lifespan. Frequent power fluctuations or surges can cause wear and tear on various parts, reducing their efficiency and overall longevity.

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State two functions of utility software

  • Repairing files
  • Compression
  • Defragmentation
  • Back up
  • Anti-virus / anti-spyware / anti-malware
  • Firewall
  • Managing application updates
  • Format disks/drives
  • System analysis tools
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Xpat ICT has been tasked to construct a network for an organisation. Explain three factors that the company should consider when selecting the medium for the connectivity (KCSE 2021 Computer Studies Q19c)

  • Security
  • Installation cost
  • bandwidth the medium can support
  • Flexibility e.g wireless media
  • Distance
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A family has purchased a computer system with the following specification:

Processor speed 2200 MHz
RAM 512 Megabyte
Hard disk drive 120 Gigabytes
CD ROM
DVD writer
Modem 56k
Monitor 17"

(a) The computer has been purchased for buying goods and services over the Internet. Explain how each of these items of hardware would be used for this purpose.

Hard disk drive

RAM

DVD writer
Modem

Hard disk drive

  • to hold the operating system/communication and applications software/ISP software
  • for storing files/information/cookies on backing store

RAM

  • for data, computer programs and operating instructions which are moved into it/downloaded for data currently in use

DVD writer

  • Films/videos/pictures/music/multimedia data downloaded/purchased

Modem

  • link/dial up/establish communication with the Internet
  • Convert digital signals to analogue/audio tones (and vice versa) Which can travel across the telephone system
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State two advantages of electronic databases over a flat file

  • Data Integrity: they provide ways or mechanisms for enforcing data integrity constraints, such as referential integrity. If a record in the parent table is deleted, related records in the child table also get deleted. This ensures accurthe acy and consistency of data stored in the database
  • Data Security
  • Concurrency control
  • Reduces data redundancy
  • Data retrieval and querying
  • Data indexing
  • Data consistency and acid transaction
  • Data backup and recovery
  • Data sharing and collaboration
  • Convenient data maintenance
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Describe why fibre optic cable would be used for the backbone of the network. (2 marks)

 

Describe how the firewalls can ensure the security of the EmergWA network.

 

Describe a transmission media that would work better in remote areas

The volunteers assisting in an emergency all wear personal protection equipment (PPE) that has an RFID tag sewn into the collar so that they can be tracked if they become lost in a remote location. Identify what RFID is and outline how it works. (3 marks)

  • Fibre optic cable would be used because it has a higher bandwidth, allowing faster communication in the main part of the network. It is also more secure as it cannot be tapped.
  • Firewalls filter the data in and out of a network. Each packet is examined against the filter rules and if a packet is flagged, it is dropped. Only data packets that satisfy the filter rules are allowed through the firewall, thus providing a layer of security for the network.
  • A satellite system would be better as it does not rely on wifi, cellular etc. It is not subject to interference and is reliable in remote conditions
  • Radio-frequency identification (RFID) uses electromagnetic fields to automatically identify and track tags attached to objects. An RFID system consists of a tiny radio transponder, a radio receiver and transmitter. When triggered by an electromagnetic interrogation pulse from a nearby RFID reader device, the tag transmits digital data, usually an identifying inventory number, back to the reader. This number can be used to track inventory goods..
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Ochieng manages a network for an organisation.
(a) Two computers are assigned the same IP address.
Explain why Ochieng must change the IP address of one of the computers.

  • Devices must have a unique IP address because otherwise, a switch would not know which of the two was the correct device to send packets to

(b) Identify the network topology that requires a server.

  • Star topology

Ochieng manages a network for an organisation.
(a) Two computers are assigned the same IP address.
Explain why Ochieng must change the IP address of one of the computers.

  • Devices must have a unique IP address because otherwise, a switch would not know which of the two was the correct device to send packets to

(b) Identify the network topology that requires a server.

  • Star topology
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Explain two ways in which an interpreter and a compiler are different.

  • They execute code differently – a compiler reads a complete program at once, an interpreter reads a program line-by-line
  • they identify errors in different ways – a compiler does not allow a program to run until error-free, an interpreter runs the program until the first error.
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Describe each of the following storage devices

DVD - optical media which use one spiral track; red lasers are used to read and write data on the media surface; makes use of dual-layering technology to increase the storage capacity

ROM - non-volatile memory chip; contents of the chip cannot be altered; it is often used to store the start-up routines in a computer (e.g. the BIOS)

SSD/ Solid State Drive/memory (SSD)

non-volatile memory device that uses NAND flash memories (which consist of millions of transistors wired in series on single circuit boards)

Blue Ray -  optical media that uses blue laser technology to read and write data on the media surface; it uses a single 1.1 mm polycarbonate disc

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State the functions of the following utility programs

(a) Defragmentation software

(b) Disk contents analysis/repair software

(c) Disk formatter

(a) Defragmentation software   -   Reorganises files on a disk to improve efficiency

(b) Disk contents analysis/repair software - Scans a hard disk to identify bad sectors

(c) Disk formatter -  Prepares a hard disk for first use

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State the areas where infra-red radio waves are used      KCSE 2018

  • TV remote control communication;
  • DVD remote communication
  • Communication between peripheral devices and the computer
  • Data link over a short distance using mobile phones Radio remote control
  • Remote locking/opening doors/ devices
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Outline a factor that can influence the performance of a network.

  • The different factors that can influence the performance of a network include: bandwidth, network design, data collisions, and excess broadcast traffic.
  • The bandwidth can influence through the method of transmission and medium used
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COMPUTER STUDIES 2016 PAPER 1

  1. Identify any computer output device suitable for each of the following tasks:
  1. Generating receipts where carbon copies are required  (1mk)
  • Impact printers e.g dot matrix

     b) an architectural drawing where precision is required         (1mk)

  • Plotter

(c ) producing document output for a visually impaired person (1mk)

  • Braille/speakers
  1. Pesa Tele has offices in Nairobi and Kampala connected in a network . the management is convinced that someone is illegally gaining access to the data in their computers. State three ways in which the company can overcome this problem (3mks)
  • Encryption
  • Firewall
  • Audit trail/tracking
  • Use of passwords
  • Limit the number of log-in attempts
  1. Explain two ways in which the use of internet could make reporting of corruption easier (4mks)
  • Interactive: the internet based technology enables real-time dialogue hence instantaneous reporting of cases
  • Outreach: the technology allows the coverage of wide areas
  • Social mobilization : it easy to create a network of people with similar concerns
  • Anonymity : it is easier to report corruption without being  known
  • Security: the message sent reaches destination without being intruded
  1. State ways in which software errors can be prevent during program development
  • Use of antivirus software
  • Performing system update frequently
  • Testing the software before implementation
  • Proper training
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Differentiate between distributed data processing and time-sharing.

  • Distributed data processing is where computers located in physically separate location transmit data after processing to a server computer that updates the master file. Time-sharing on the other hand is where various terminals transmit data to be processed by a central computer's CPU. Each terminal's tasks are allocated a time slice of the CPU
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KCSE 2003 COMPUTER STUDIES

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.

 

Cell

B2

B3

C10

C11

C13

Entry

200

100

B2

B3

C10

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

            

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State what is meant by each of the following modes of data  processing

(i) Batch processing.
(ii) Real-time processing.
(iii) Online processing.
(iv) Off-line processing.

(i) Jobs collected together for processing at a later time
(ii) Output produced quickly enough to affect the next input
(iii) User has direct contact with the processor
(iv) User cannot communicate directly with the processor

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Explain each of the following function of an operating system

Job scheduling/Process scheduling                                                                                              (2mks)

  • Operating systems allocate tasks/processes/jobs to the CPU using priority and FIFO principle

 Memory management                                                                                                                  (2mks)

  • OS allocates and de-allocates memory spaces to processes loaded into the RAM
  • Swaps processes between main memory and virtual memory created in the secondary storage
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