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Q&A-KCSE Computer Studies Paper 1

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

Fibre optic cable is available in either single-mode or multi-mode. Outline the characteristics of each mode.

  • Single-mode fibre consists of a narrow core in which all light pulses travel at the same speed and arrive roughly at the same time at the destination.
  • Supports higher bandwidth with less signal loss over a greater distance
  • Multi-mode Multi-mode fibre consists of a larger core in which multiple light pulses can travel down the core.
  • Supports a smaller bandwidth and signals attenuate at a shorter distance than single mode fibre.

Students are using their wireless notebooks to complete their work in a classroom. They will need to connect wirelessly to a printer to print their answers at the end of the lesson.
Describe how CSMA/CA (Carrier-sense multiple access with collision avoidance) operates in the above scenario.

  • All nodes ‘listen’ for traffic to sense when the network is idle.
  • When a node wishes to transmit, it transmits a ‘request to send’ frame’ (RTS)
  • The intended receiving device will transmit a ‘clear to send’ (CTS) frame if it is available.
  • All other nodes ‘sense’ the network is busy and wait a random amount of time before trying to transmit

802.3 is the standard for ethernet wired networks and 802.11x is the standard for ethernet
wireless networks.
Outline why standards such as these are important in the development of network devices and
software.

  • Standards specify a set of rules for hardware and/or software used in network communications. Because all manufacturers must adhere to the standards when manufacturing network hardware or software, it means that all devices should be able to communicate, regardless of manufacturer.

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..

Outline any 2 Examples of wireless transmission media       (2marks)

  • Radio waves
  • Microwaves
  • Infrared waves

An organisation that supplies audiobooks over the internet is moving into a new office building.
 (a) One reason for networking devices is to provide access to the internet.
  (i) Give two other reasons for connecting devices to networks.
 

  • Share peripherals/devices (e.g. printers, scanners)
  • Communicate (e.g. email, instant messaging, play games)
  • Share data (e.g. files/music/videos/backups on servers)
  • Deploy/update applications
     
     

(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

(b) Routers have an important role in how the internet functions.
  Describe how a router directs data on the internet.

  • Reads the data/packet to find the recipient's address 
  • Has physical connections to >=2 different networks
  • Holds a routing table
  • Stores information about (IP) addresses 
  • Keeps packets inside a network by not forwarding them 
  • Forwards data / directs/forwards/sends packets 
  • Chooses the most efficient path to the next node

A large comprehensive school has over 500 computers connected to their Local Area Network (LAN) with a connection to the Internet. (a) Describe, in detail, four disadvantages for the school of having a network of computers compared to stand alone computers

 A network manager may need to be employed  which might be expensive

Could be infected with a virus that could spread to all other computers

Security problems receive traffic from other networks

Hackers may gain access as the network only as secure as weakest point of entry to data and steal/destroy

 The server/switch could go down (main cable break) so all workstations on the network are affected

 Can be expensive to set up as Initial cost of servers, communication devices, switches, network software etc. 

 Substantial Initial disruption: drilling holes, fitting trunking, running cables between buildings etc… 

 Can have a slow response time  due to heavy network traffic so users cannot work as effectively

 Detecting network problems can be more difficult on a network i.e difficult to isolate

 Can be slow to log in to a network  As it slow to download software/check password

 Only limited storage space available on network while one has access to all hard disc drive on standalone computer

 Time and effort to set up users o Can just start a standalone and use computer

Distinguish between microwave and a radiowave transmission and a microwave transmission  (KCSE 2017 PP1)

Microwaves can cover shorter distances. On the contrary, radio waves can travel a long distance. Radio wave is usually propagated through sky mode while microwave uses the line of sight propagation. 

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.

 

State examples of wireless transmission media

  • Broadcast Radio
  • Infrared
  • Bluetooth
  • Microwaves
  • Satellite

State three functions of  a network  operating system

  • Allows creation and management of user accounts
  • Helps in troubleshooting of the network
  • controls access to network resources
  • Provides communication services
  • configures network resources
  •  

 

State advantages of star network topology

  • Easy to add nodes
  • Managed centrally
  • Fewer data collisions
  • A single node failure does not affect the rest of the network


Interfaces enable computer users to interact with the operating system. State three advantages of using a graphical user interface (GUI) for loading programs and files.

  • novice can use the system right away
  • user-friendly/easy to select
  • click on icons/picture to select
  • easier to input/words are replaced with icons
  • no need to know command language to use the system/remember
  • command language
  • selecting item using mouse is faster than entering commands
  • avoids typing errors
  • no need to type
  • no need to remember commands
  • no need know the different commands for the different software
  • multitasking (several programs open at the same time therefore easier
  • /faster to switch
  • easier/faster switching between files, folders etc.

What is a computer keyboard?

A computer keyboard is an input device used to enter text, characters, and various commands into a computer or other digital devices.

Explain each of the following function of an operating system

Job scheduling/Process scheduling                                                                                              (2mks)

  • Operating systems allocate tasks/processes/jobs to the CPU using priority and FIFO principle

 Memory management                                                                                                                  (2mks)

  • OS allocates and de-allocates memory spaces to processes loaded into the RAM
  • Swaps processes between main memory and virtual memory created in the secondary storage

State three factors to consider when selecting an operating system to install in a computer        (3 marks)

  • Ease of installation and use
  • Application software intended for use in the computer
  • Processor type. Some processors do not support all operating systems

IT technicians are setting up a new file server for a school. Describe the benefits and drawbacks of using a command line interface (CLI) rather than a graphical user interface (GUI) to set up a new file server.  (4marks)

Benefits

  • The user is not restricted to the predetermined options//the GUI uses icons and set menus
  • The user has more control over the computer settings//in GUI computer settings are protected from the user
  • Uses less memory than GUI
  • Requires less processing power for the interface
  • More processing power is made available for the task

Drawbacks

  • The commands used have to be learnt
  • The commands used have to be remembered
  • The commands used have to be typed in/entered exactly
  • Have to remember the exact path/correct name of application
  • More prone to errors on data entry Commands have to be typed in//in a GUI can use touchscreens/mice
  • Tends to be used by specialist people//GUI is more user-friendly and can be used by non-experts