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Q&A-KCSE Computer Studies Paper 1

State a stage in system development where each of the following activities are carried out    (KCSE 2018)

(a) Identifying technologies that may be used in a proposed system

  • System Analysis/Information gathering/Problem recognition

(b) Identifying the shortcomings of the old system

  • Problem definition

(c) Prepares the software migration plan

  • Implementation stage
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Give three examples of how data can be damaged accidentally

  • Power surge/loss (damages hardware)
  •  Use a UPS
  • Water can be spilt on the device
  • Don’t have water near the device
  • Keep the device in a waterproof box when not is use
  • Fire can destroy the device
  • Use electrics safety
  • Keep the device in a fireproof box when not in use
  • Data is accidentally deleted
  •  Add verification method for data deletion
  •  Set access levels for data to limit who can delete the data
  • Incorrect use of storage device
  • Making sure the device is ejected before removing
  •  Physical damage to hardware // hardware failure
  •  Correct care and maintenance of hardware
  •  Software failure 
  • Making sure it is always up to date // enable automatic updates

 

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Identify the protocol used to transfer data in networks.

  • TCP/IP
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Explain what is meant by the two terms download speed and upload speed

download speed :
– speed at which information/data is transferred FROM server/Internet
– speed at which information/data is transferred TO the user’s computer
upload speed :
– speed at which information/data is transferred FROM user’s computer
– speed at which information/data is transferred TO the Internet/server

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Why must operating system be installed in a computer before any other program

  1. Operating system manages the computer hardware thus without it the programs cannot communicate directly to the hardware
  2. Provide a user interface through which a user can give instructions to the computer. Without a user interface, it would be difficult to load or run programs
  3. other programs depend on the operating system to load them into the memory , allocate resources and schedule processor time, Without operating , there would be nothing to co-ordinate the execution of multiples programs
  4. The OS organizes data in files and directories, making it possible for programs to save, retrieve, and modify data.
  5. Without it, programs wouldn’t know where or how to store data.
  6. The OS controls access to files, memory, and devices, ensuring that one program doesn’t interfere with another.


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Differentiate between action query and select query

An action query is used to modify, add, or delete data in a database whereas a select query is used to retrieve data from a database based on specified criteria but does not make any changes to the data.

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Explain two ways in which an interpreter and a compiler are different.

  • They execute code differently – a compiler reads a complete program at once, an interpreter reads a program line-by-line
  • they identify errors in different ways – a compiler does not allow a program to run until error-free, an interpreter runs the program until the first error.
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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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b) Give one benefit of each type of data transmission

Serial

  • -more accurate/fewer errors over a longer distance
  • -less expensive wiring  
  • less chance of data being skewed/out of synchronization/order
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Differentiate between modulation and demodulation as used in data communication

Modulation refers to the process of converting a digital signal to analog signal at the transmission end while demodulation is to converting analog signal to digital signal at the receiving end

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Describe the purpose of two registers that are used by Von Neumann architecture.

MAR( memory address register)

  • Stores the address/location where data will be read/written/accessed/fetched
  • stores address/location of data/instruction being processed
  • stores address/location of data/instruction next to be processed

MDR or  memory data register

  • Stores the data/instruction that is fetched/read from memory
  • stores the data that is to be written to memory
  • stores the data/instruction from the address in the MAR
  • stores data/instruction next to be processed

 Program counter

  • Stores the address/location of the next instruction to be run
  • stores the address/location of the current instruction being run

Accumulator

  • Stores the result of manipulation/process/calculation
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(ii) State what ROM and RAM store.

 

ROM stores BIOS / bootstrap / start-up 

RAM stores currently executing programs and data

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Internet and E-mail Questions

Define the term internet      1mk

  • The global interconnection of computer networks for purpose of communication and resource sharing

Explain the term web page    1mk

  • A hypertext  page prepared to display the content on the web

Explain the following internet address http://www.google.co.us in reference to the structure of a URL    3mks

  • HTTP- hypertext transfer protocol or simply protocol
  • WWW – subdomain
  • google – the name of the computer with the web content/domain name
  • .co – top level domain for commercial organization
  • .us- a TLD extension for the country US

 

What is the world wide web                                       1mk

  •  A virtual space on the internet that allows web pages and sites to be accessed

Define the term browser                                    1mk

  •  A software that used viewing of web content

Explain the meaning of the word hyperlink     1mk

  • A text or picture that is a link to another webpage on the internet

What is a search engine?     1mk

  • Is a special program that collects and stores links to information websites allowing users to search its database for them
  • A specialized web-based application that help the user to search for specific information on the internet.

Explain the meaning of the term internet service provider            1mk

  • A company that offers internet services to end-users

Identify three elements apart from a computer that is required for one to be connected to the internet    3mk

  • Modem
  • Internet software
  • Internet service provider
  • Telecommunication lines
  • TCP/IP protocols

 

Define the term modem 1mk

  • Stands for modulator-demodulator
  • A device that enables telecommunication to use telephone lines

What is a protocol? Write the following in full: TCP/IP, HTML, HTTP and FTP           5mks

  • Protocols – are special communication rules that govern sending and receiving of messages by computers on a network
  • Html – hypertext markup language
  • Hypertext transfer protocol
  • Transmission Control Protocol
  • Internet Protocol
  • File Transfer Protocol

What would you do if a website refused to load on the browser within the first attempt?   1mk

  • Click the refresh button on the toolbar

 State three internet services                         3mks

  • Instant messaging
  • E-mails
  • E-commerce
  • Social media and networks
  • E-learning

 

Define the term internet telephony      1mk

  • Transmission of voice data over the internet

State three benefits of the internet in our society

  • Provides a platform for conducting business and marketing
  • Provides many platforms such as social media through which people can contact each other
  • Cost saving
  • Efficient communication

What is a utility software?

The following are some of the possible definitions:

It is system software designed to help the users to analyse, configure, optimize, or maintain a computer

System software that helps maintain the proper and smooth functioning of a computer system

Examples include antivirus software, Disk clean-up tools, disk defragmenters, backup software, etc

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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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
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Explain the term proofreading as used in word processing (2mks) [kcse 2017 Paper 1]

  • It is the use of proofing tools like spelling and grammar checkers and autocorrects to check whether a document has typographical or grammatical errors
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Describe each of the following types of a program errors, giving an example in each case.

(i) Syntax error.
(ii) Logic error.
(iii) Arithmetic error/runtime error

(i) Incorrect use of language, e.g. PLINT instead of PRINT
(ii) A mistake in the structure of the solution, e.g. a jump goes to the wrong line
(iii) Inappropriate arithmetic is used, e.g. division by 0 is attempted

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Using an example, explain a difference between a primary key and a foreign key in a relational database.

A primary key is a table field that uniquely identifies each record and ensures that duplicate entries are not allowed

A foreign key is primary key of a parent table placed in a child table to ensure that any record added to a child table is related to the one in parent table.


A foreign key is a field (or a set of fields) in one table that refers to the primary key of another table. It is used to establish and enforce a link between the data in the two tables, ensuring referential integrity.

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Explain one benefit to a user if the program is distributed as free software

  • The user can access the source code  so, they can tailor the software to their needs and they can fix any bugs in it
  • the source code could be studied for educational purposes
  • The user can redistribute the software/program  but this must be done under the same terms as the original software
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