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Q&A-KCSE Computer Studies Paper 1

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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Give any three advantages of computer networks

  1. Enable resource sharing
  2. Facilitate remote communication
  3. Enable distributed processing
  4. Provide better data security and management

What is a web browser?

  • A software which can display a webpage on a user's computer screen
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Describe how the database can be recovered from a system failure

  • backups/dumps of files
  • copy of files on CD/tape streamer
  • file generations
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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.

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Distinguish between Incremental and Full backup


Incremental:

  • Only the changes need to be backed up
  • The software/OS/settings are unlikely to have changed between backups
  • Small number of files likely to be used/edited between backups
  • Take less time to backup
  • Each backup will take less memory space to store

Full:

  • Backup all the data/files and software
  • It might not take a significant time to back up entire system
  • He might only have a small number of files to be backed up each time
  • Safer as have more past versions to revert to
  • User may have changed settings on computer
  • Faster to restore the backup
  • Needs to do a full before he can do an incremental
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(ii) The organisation has chosen wireless connectivity over wired connectivity for its new office building. There is no significant difference in the cost of installing either.
Give three reasons why the organisation might prefer wireless connectivity.

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

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Explain the Fetch – Execute cycle and provide an example of a Central Processing Unit (CPU) component for each stage of the cycle

The Fetch – Execute cycle is a sequence of actions, performed by the processor as it fetches
a program instruction from its memory, determines what the instruction wants to do and
carries out those actions. The stages of the cycle are provided below.

  • Fetch the instruction – the processor fetches the instruction from a memory address stored in a program counter and transfers the instruction, via a data bus, to an instruction register. At the end of the fetch operation, the counter points to the next instruction that will be read in the next cycle.
  • Decode the instruction – the processor decodes the instruction stored in the instruction register, including getting any operands required to complete the instruction.
  • Execute the instruction – the decoded instruction is executed.
  • Store the result – the result generated by the execute phase is stored in the main memory, and/or sent to an output device. The program counter is updated with feedback from the arithmetic logic unit (ALU), to a different address from which the next instruction will be fetched.
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Describe one task that is commonly undertaken during the first phase of system development life cycle

  • 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
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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 three categories Operating Systems grouped according to user interface

  • Commandline/ Character interface Operating systems
  •  Menu Driven Operating Systems
  •  Graphical User Interface Operating Systems
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Give one reason why use of video-conferencing has increased over the last ten years.

– faster communications now widely available
– safety reasons, e.g. increase in terrorist attacks on international flights
– reduced transportation/accommodation/hardware costs
– environmental issues, e.g. reduced carbon footprint
– increase in multinational working

State two reasons for carrying out software updates

  • To get the latest features
  • To update security features
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Name four data management tools used in spreadsheets. (2 marks)
- Filtering - Sorting - Input validation - Subtotals - Data entry forms
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Describe the following features of a graphical user interface:

(a) Pointer

(b) Desktop

(a) Pointer

  •  A graphical object on a computer screen that responds to move movement and allows the computer user to select and execute commands in graphical user interface operating systems

(b) Desktop

  • It Is a special folder in the file system that is displayed when no other windows are open
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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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Explain how an SSD stores data

Uses transistors( resistors and capacitors) . It can be implemented by the use of NAND or NOR gates. Data is stored on the chip as a charge

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Explain how virtual memory can compensate for the limited  RAM capacity in a computer.

  • VM is used when RAM is full  i.e part of the secondary storage used as (temporary) RAM/VM
  • Data from RAM is moved to the secondary storage/VM (to make space in RAM)
  • RAM can then be filled with new data
  • When data in VM is needed it is moved back to RAM
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Mikal has been employed as a computer trainer in an organisation. State three roles that she is likely to play in the organisation

  • Developing training materials
  • Training computer users
  • Conducting ICT examinations
  • Managing the learning and examination process
  • Developing guidelines for using the computer lab
  • Planning the course content
  •  
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State two benefits of using robots

  • reduced labour costs/do not need paying
  • reduced cost of goods
  • improve speed of production/productivity
  • high degree of accuracy/precision/less errors
  • can operate where humans can not go
  • do not take breaks/holidays/get tired
  • work 24 hrs a day
  • reduce accidents at traffic lights
  • improve traffic flow
  • can work in dangerous conditions