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Q&A-KCSE Computer Studies Paper 1

Give two reasons for connecting computers in a network.
Can share files/data Can share applications/software Can collaborate Can share peripherals (printers, speakers) Can share connectivity (Internet connection, hotspot) Can access files from any computer / hot desk Central control/management (security, software updates, backup, remote support, users, remote monitoring) Allows communication (email, social media, video conferencing, online meeting, collaborative games)
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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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Define the term variable as used in programming

A variable is a memory location used to store a value

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Give a reason why microwaves are commonly used for point-to-point communication

  • their small wavelength allows conveniently sized antennas to direct them in narrow beams, which can be pointed directly at the receiving antenna
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Distinguish between operating system software and an application software

  • OS controls operation of system/hardware
  • Applications software allows the system to do something useful
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A company has decided to deliver its products online to international customers. It has employed you as a project manager to determine whether this is a viable business decision. You choose to conduct a feasibility study. Outline the purpose of a feasibility study using two components associated with this process.

  • It covers many aspects that will be used to decide whether to go ahead with the project or not.
  • The main components are technical, operational, economic, legal and scheduling.
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A web server has an internet protocol (IP) address. Give three characteristics of an IP address.

  • consists of values between 0–255 / 0–FFF
  • values are separated by full stops/colons
  • it is a unique address
  • can be static or dynamic
  • can be public or private
  • can be IPv4 / have four groups of digits
  • can be IPv6 / have eight groups of digits
  • in IPv6 :: can replace groups of zeros.
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Ahmed uses the Internet for some time and is puzzled by the terminology.
(a) Draw a line to match each description to the appropriate technical term.

  • a computer that responds to requests to provide information and services over the Internet - an Internet server
  • defines how messages are transmitted and formatted over the Internet-HTTP
  • software that enables users to access/view documents and other resources on the Internet - Browser     
  • numerical ID for each device on the Internet-IP address
  • unique ID for a network interface card  -MAC address
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Give three features of a data protection act.

  • data shall only be used for the specific purpose for which it was collected
  • data shall be adequate/relevant/not excessive
  • data shall be accurate/up to date
  • data shall not be kept any longer than necessary
  • individuals have the right to see data about them (and have it changed if inaccurate)
  • sufficient means taken for security/integrity of data
  • data shall not be transferred to a country with lower protection laws
  • data users must be registered
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Explain a reason necessitating  governments to enact data protection laws

  • To provide legal backing so that it is possible to seek redress if the rights are violated
  • To observe copyright for those who create original works
  • To protect the confidentiality of information kept  about an individual
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A supermarket uses point of sale (POS) terminals at the checkout for scanning barcodes on the products.

(a) State two items of data that are stored on the barcode.

(b) Describe how the computer system checks that the barcode has been read correctly.

(c) State the type of file access that is used to get the price from the central computer.

(d) Explain how the system updates the file when an item has been sold.

(a) State two items of data that are stored on the barcode.

  • check digit
  • product number/item number/code
  • country of origin
  • manufacturers number/code
  • weight
  • price

(b) Describe how the computer system checks that the barcode has been read correctly.

  • check digit calculation is performed on the check digit, remainder = 0 if the barcode has been read correctly
  • weights and modulus 11 and use remainder
  • or subtractions and addition and use answer


(c) State the type of file access that is used to get the price from the central computer.

  • random/direct/online

(d) Explain how the system updates the file when an item has been sold.

  • search file/master file using barcode number/product code and decrease number in stock/increase quantity sold

Define patch as used in the operating system

Refers to a small piece of software designed to update, fix, or improve a specific part of the operating system or an application.

NB: Patches are typically released by the software's developer or the operating system vendor to address security vulnerabilities, software bugs, or to add new features or enhancements

1 (a) Computer networks are valuable to many businesses and individuals.
(i) State the purpose of network protocols

Any one of:
To allow connected machines to communicate
To provide the rules of communication between two networked devices

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Explain why solid state storage is the best choice for a fitness tracker.

  • Because it will be subject to movement  and it does not use mechanical/moving parts

          OR

  • Solid state storage is smaller/more compact so better suited for a wearable device

          OR

  • Doesn’t have moving parts  because they could be disrupted during use
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Outline any 2 Examples of wireless transmission media       (2marks)

  • Radio waves
  • Microwaves
  • Infrared waves
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Define Domain integrity

Domain integrity - ensures that all data in  a field contain valid values

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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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State four tasks performed at the analysis stage in systems analysis.

  • understand the current system
  • produce data flow diagrams/system flowchart
  • identify user/client requirements/objectives
  • interpret user/client requirements/objectives
  • agree requirements/objectives with the user/client
  • collect data from the current system
  • fact finding (e.g. questionnaires, interviewing, etc.)
  • problem identification
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Define an end user license agreement (EULA).

  • An end user license agreement (EULA) describes a contract (agreement) between a software developer and a user of that software.
     
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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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