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Q&A-KCSE Computer Studies Paper 1

(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

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Explain, using examples where appropriate, the meaning of these computer terms

(a) byte ..................................................................................................................................
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(b) compiler ............................................................................................................................
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(c) handshaking .....................................................................................................................
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(d) technical documentation ..................................................................................................
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(e) simulation .........................................................................................................................
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(a) byte

  • fixed number of bits, 8 bits
  • represents a character


(b) compiler  program

  • converts/changes/translates high-level language into machine code/machine language/low-level language/object code
  • changes each high-level language instruction into machine code instructions
  • produces an independent program capable of being executed by itself
  • all (syntax errors) listed
  • converts the whole program before execution/in one go
  • converts source code to object code

(c) handshaking

  • exchanging of signals to establish communication between two devices/computers e.g. printer and computer, modem and computer

(d) technical documentation

  • documentation to ensure that the system can be maintained/updated/altered/developed/upgraded
  • trouble shooting/correcting errors/correcting faults
  • explanation of what the program does/how the system works
  • contains file structures
  • algorithms/flow charts/pseudo code
  • program listings
  • hierarchical chart

(e) simulation

  • studying the behavior of a system by using a model/represents real-life/mathematical representation
    e.g. flight simulator (or others), hazardous applications results can be predicted
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Which files are backed up in an incremental backup scheme?

  • Any new or changed files since the last backup
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Describe what is meant by ‘RAID 10’.

  • RAID 10 is a combination of RAID 0 (zero) and RAID 1 (one)
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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 how a FRID works.

RFID stands for radio frequency identification. There is an RFID reader and tag.RFID is used in contactless credit and debit cards as well as in some hotel room cards. Inside an RFID tag is a chip that contains a small amount of memory. The chip is attached to a coil of wire which acts as an antenna. When an RFID tag is scanned, the reader emits radio waves which are picked up by the tag’s antenna. The power induced in the tag’s antenna from these waves is enough to power the chip which then uses its antenna to emit its own radio wave, which contains the information held on the chip. This wave is picked up by the reader which decodes the information and returns the information to a computer.

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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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State two benefits of using computerised traffic control systems

  • Detecting congestion.
  • Synchronizing activity between traffic lights.
  • Updating traffic light timing in real time.
  • Updating and informing drivers of ideal speeds.
  •  Prioritizing transportation flow.
  •  Reduce congestion and time spent on the road
  • By reducing congestion it will decrease pollution
  • Prioritize traffic based on changes in traffic conditions in real time.
  • This system is also helpful to reduce infrastructure damage. It is possible to identify overloaded vehicles and provide them with appropriate ways or roads, which will reduce road damage.

When data is transmitted it is subject to corruption. Explain how a parity check could be used to determine whether corruption has taken place.

  • Extra bit on each data-byte that
  •  Does not transmit data
  • Makes the number of ones in a byte always even or always odd
  • Error in the transmission of a bit will make the even/odd wrong
  • The problem of two errors in one byte not being found
  • Parity block
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State any four applications of electronic spreadsheets

  • Financial accounting
  • Prediction and forecasting
  • Inventory keeping
  • Budgeting
  • Keeping records
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Distinguish between application and system software

  • Application software refers to software that is designed to help the computer user to accomplish specific tasks
  • Examples of application software include; Internet browsers, word processors, spreadsheets, databases etc
  • System software is software that performs tasks needed to operate the hardware and provide services to other software
  • Examples Operating Systems, Networking software, utility programs(encryption, backup, disk defragmentation software, ...)
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State advantages and disadvantages of Solid State Drives and Hard Disk Drives

Advantages of  of Hard Disk Drive

  • Hard disk drives are cheaper per gigabyte than solid state drives.
  • Hard disks have a longer lifespan than solid state drives

Disadvantages of Hard Disk Drives

  • Consumes more power than SDD
  • They are noisy.
  • They are slower than solid state drives.
  • They are susceptible to wear and tear as they have movable parts.

Advantages of Solid State Drives

  • Are faster than HDDs
  • It is more durable as it does not have moving parts
  • Consumes less power
  • Are not noisy

Disadvantages of SDD

  • It costs more than a conventional hard disk
  • Have fewer write/erase cycles compared to a hard disk drive
  • Lost data cannot not be recovered
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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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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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Explain the term website as used in the internet

  • A collection of related webpages under the same domain name
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State three ways of transforming a picture embedded in a DTP program in order to fit on a designated space on a document (kcse 2019 paper 1)

  • Resizing using resize handles
  • Rotating
  • Cropping
  • Flipping
  • Moving
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What is an Operating System?

  • It refers to a system software that provides a platform for installation and execution of an application software and also manages the computer hardware
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  1. (a)State the meaning of the term disk defragmentation as used in computers  (1mk)
  • The process of rewriting parts of a file to contiguous sectors on a disk
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Shaneela is designing and coding a website. The files she creates will be stored on
a computer.
(a) File management is a function that an operating system performs.
Describe how an operating system organises files

The organisation of files is in a hierarchy/tree structure
A node is either a folder/directory/sub-folder/sub-directory or the file itself
The top node/folder/directory/drive is the root

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What is a web browser?

  • A software which can display a webpage on a user's computer screen
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