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Q&A-KCSE Computer Studies Paper 1

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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6 Programmers write software that controls hardware and interacts with users. Some of this software ensures that networks function properly.

(a) Compilers and interpreters translate source code written in programming languages.
  State four other features of a compiler.

 A single executable file is produced 

The executable program is portable between machines

The program source code is not available

Code can be optimised/made more efficient 

Entire source code file is converted at once

No special environment is needed to execute the code 

It creates object/machine code

Error report is provided at the end of the compilation

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Distinguish between a client-server and a peer-to-peer network

  • In a client-server network, every device is either a client or a server whereas in a peer-to-peer network each computer has equal responsibility and each has the ability to work as both a server and a client
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Explain each of the strategies listed below.

(a) Phishing

(b) DoS

 

(a) Phishing

  • Phishing is a strategy that encourages a computer user to part with sensitive information such as bank details hence the term ‘phishing’ – i.e. fishing – trying to catch someone out. For example, a perpetrator sends a user an email that appears to be genuine, for example, pretending to be a bank or a lawyer requesting that the user verify bank account details or send money to assist in the completing of a legal case.

(b) DoS

  • DoS is a means of attack on a specific user/system/website which involves overloading a target with too much network traffic resulting in system slowdown, shutdown or a violation of security.
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Describe two methods used to assist in finding program errors.

  • Use of debugging utilities
  • Use of test data
  • Dry run / Desk checking
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Name two other input/output devices used at the POS terminal apart from keyboard and barcode reader and give a use for each device.

device: beeper/loud speaker
use: to indicate barcode correctly read/error in reading barcode
device: (LCD) screen/monitor
use: to show prices and other information about goods
device: touch screen
use: to show prices and other information about goods/to select items that need to be
weighed/identified
device: weighing machine
use: to find weight of loose items (e.g. fruit) to enable pricing
device: (magnetic) card reader/CHIP and PIN reader
use: to read customer’s debit/credit card/enable customer to pay for goods using a
credit or debit card
device: printer
use: to print receipts

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Distinguish between an optical scanner and a magnetic ink scanner

  • Optical scanner is used read data by use a beam of light while a magnetic ink scanner is used to read data encoded/written using magnetic ink by magnetising the ink characters and translating them
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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
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Joe plays online games using the world wide web. A sequence of processes is required to open a web page. Describe this sequence of processes

  • URL is clicked/typed into a web browser address bar. The page is requested (by the web browser) so HTML and files are fetched from a web server and the browser collates the page, which is then displayed on the monitor.
  • OR
    URL is clicked/typed into a web browser address bar (1). The browser locates the IP address either in cache or using a DNS server and the browser sends a request to the web server with that IP address web server uses HTTP to send back the requested web page and the browser displays the content of the page .
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State two data protection rules that should be obeyed by all staff in a hospital.

  • data must be accurate/up-to-date
  • personal data must be registered
  • data must be used for the purpose that is registered for
  • if data is to be used for another purpose the registrar must be notified/
  • subject gives consent
  • patients must be able to see the data and have it changed if it is incorrect
  • processed fairly and lawfully
  • kept no longer than needed
  • kept secure
  • not transferred to other countries without protection
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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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Utility software are operating system programs designed to maintain the functionality of a computer system.

Describe three types of utility software that are provided to help maintain the security and integrity of computer data.

  1. Virus scanning / Anti-virus. Used to locate and delete viruses / scans and compares files with databases of known viruses.
  2. Firewall: checks data packets / examines source address / filters out unexpected packets.
  3. Back up. Copies data onto a separate storage device for use if the original data is lost or corrupted.
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State the uses of 3D printers

  • Making prosthetic limbs for patients
  • Making items which allow precise reconstructive surgery
  • Making light-weight plane wings
  • Making sculptures
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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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What is an information system ?  (KCSE 2012))

Is an arrangement of people, data, processes, communication and IT that interact to support problem solving

 

Components of an information system

  • Hardware
  • Software
  • Data - information manipulated by software
  • people- all people involved
  • Processes - steps to accomplish a goal
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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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What is a computer system ?

A computer system refers to computer components that collectively function as a single unit to achieve the desired goal. It can also be defined as a collection of hardware, software, and liveware that work together to receive, process, and manage data

List two primary functions of a domain name server.

  •  map IP addresses to names and criteria
  • To map directory services
  • Maintain directory of domain names
  • To map URL (web address) to IP address
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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

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.

 

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