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Q&A-KCSE Computer Studies Paper 1

Distinguish between one to one and one to many relationships as used in relational databases

One to one  - Each record in the parent table has exactly one related record in the child table, and vice versa.

One to Many -  Each record in the parent table can have multiple related records in the child table, but each record in the child table is related to only one record in the parent table

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A protocol is used to securely transmit the data for the website to the browser.
(i) State the name of this protocol.

(ii) Identify how this protocol changes the data to transmit the data securely.
 

(i) State the name of this protocol.   HTTPS 

(ii) Identify how this protocol changes the data to transmit the data securely.

  • It encrypts it
  • It applies encryption algorithm
  • It applies an encryption key
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There are many different types of errors that can occur when developing computer programs. (a) State the name of the two different types of programming error described below.

(i) Unexpectedly halts the program.

(ii) The program produces the wrong output. 
 (b) Another error can result from incorrectly using the rules or grammar of the programming language.

(i) Name this error. 

(ii) State when this error is detected.

 

(i) Unexpectedly halts the program. Run time (execution)

(ii) The program produces the wrong output.  Logical
 (b) Another error can result from incorrectly using the rules or grammar of the programming language.

(i) Name this error. Syntax

(ii) State when this error is detected.

Syntax error is detected during translation into executable code / attempted to run but fails

State THREE reasons why binary is used in developing digital electronic systems                                                                                                                                                   (3marks)

  • Simple technology is needed to develop both hardware and software.
  • Digital devices are more reliable, small in size and use less power as compared to analog devices.
  • Devices that read, process or output data in digital form are used in computers and other digital devices such as calculators.
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Programmers use trace tables with algorithms. Explain the purpose of a trace table.
It helps the programmer visualise the steps in a program / find errors/bugs / check the algorithm gives the correct output (1) because they can see the value a variable holds at a given point in an algorithm (1)
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What are the functions of the system clock in the CPU?

  • It dictates the speed at which data is transferred between these components and enables the sequential execution of instructions in the correct order.
  • generates a timing signal that is used to synchronize communication between CPU components and the rest  of the computer system
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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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State one advantage and one disadvantage for customers of using the Internet for shopping.
 

Advantages

  • on-line catalogues can be viewed
  • much larger choice of products
  • product reviews obtainable before purchase
  • orders placed over internet any time day or night
  • download software purchased straight away
  • good and services usually cheaper on the internet
  • programs that can search for best price/cheapest
  • very fast placing an order has been placed as customer name, address
  • and credit card details are stored so no need to re enter
  • buy goods from anywhere in the world
  • no need to go to shop/save travelling time

Disadvantages

  • spam
  • need a credit card to shop on-line/not everyone has a credit card
  • hackers could retrieve credit card numbers and use them to buy goods
  • security fears - of giving credit card number over the internet/fraud
  • goods must be delivered/can not have the goods immediately
  • can not touch/handle/see the goods
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State four factors to consider when acquiring computer software

  • Authenticity
  • Users' needs
  • Availability of documentation
  • Cost
  • Compatibility
  • Upgradability
  • Portability
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What is a Uniform Resource Locator?

  • It is an address to a resource on the internet
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(a)State what is meant by the terms:

Parallel data transmission...................................................

Serial data transmission......................................................

(a)State what is meant by the terms:

Parallel data transmission

  • 8 bits/1 byte/multiple bits sent at a time  
  • using many/multiple/8 wires/lines

Serial data transmission

  • one bit sent at a time over a single wire
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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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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 one ethical responsibility of software users

  • Users need to ensure that their software is licensed
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KCSE 2016 COMPUTER STUDIES PAPER 1

A manager wishes to replace the current manual system with a computerized one. Describe three areas that must be evaluated to justify the replacement  (6 marks)

  • Technical feasibility
  • Does the current technology suffice
  • Economic feasibility
  • Benefits outweigh costs/ whether the project is cost effective
  • Schedule feasibility
  • Can it be done within the schedule

Headache, back and neck pain may result from the use of computers. State how each of them can be minimized (2mks)

  • Proper lighting
  • Regular breaks
  • Use of antiglare
  • Correct position of the screen
  • Ergonomic furniture

Students of a school intended to elect their school Captain by secret ballot.  State three ways in which computers can be used to improve the election process                           (3mks)

  • Registrations of voters
  • Voter identification
  • Actual voting
  • Tallying
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Describe the difference between a barcode and A quick Response code (QR code)

  • A barcode is one-dimensional while a QR code is two dimensional
  • Barcodes are a set of vertical lines and QR code contains squares
  • QR codes can be read from any angle . Barcode is only above or below and lined up horizontally
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A company has a website that is stored on a web server.
(a) The website data is broken down into packets to be transmitted to a user.
Describe the structure of a data packet.

  • it has a header that contains the destination address, the packet number, and the originator’s address
  • it has a payload
  • it has a trailer.

 

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Explain how the techniques of

(i) verification,
(ii) validation
are used to ensure that the stored data is as accurate as possible.

Dual input of data

  • Two inputs are compared by the system and any discrepancies are reported (and not stored.)
  • Data input once, either printed out or checked on the screen and  errors corrected

 Rules are given to the processor

  • Only accept A, B, C, D, E, F, G i.e Any other input rejected.

Drop-down list/radio buttons

  • Provides only valid inputs, so no other validation is required
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Explain the difference between
(i) serial and parallel,
(ii) simplex and duplex
modes of data transmission.

  • Serial is the transmission of data one bit at a time/through one wire
  • Parallel is the transmission of data more than one bit at a time/many wires
  • Simplex is the transmission of data in one direction only
  • Duplex is the transmission of data in both directions simultaneously
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What is entity integrity?

  • It ensures that each row has a unique and non-null primary key
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