admin@kcseforecast.com

Q&A-KCSE Computer Studies Paper 1

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)

 Identify the type of software used to compress files.

Utility Software

State any four applications of electronic spreadsheets

  • Financial accounting
  • Prediction and forecasting
  • Inventory keeping
  • Budgeting
  • Keeping records

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

Describe and give an example of one syntax and one logical programming error.

Syntax
An error that occurs when a command does not follow the expected syntax of the language, e.g. when a keyword is incorrectly spelt
Incorrect: IF A ADN B Then
Correct: IF A AND B Then

Logical
An error that causes a program to output an incorrect answer (that does not necessarily crash the program)
An algorithm that calculates a person’s age from their date of birth, but ends up giving negative numbers

Explain why a software developer should be responsible for addressing ergonomic issues in software design.

Responsibilities of the software developer is to ensure that the ergonomics focuses on making software user-friendly, reduces repetitive motions or eyestrain and enables movements of users to promote comfort and efficiency.

Software can be designed with adjustable text sizes and screen brightness settings to prevent eye strain, offering users a way to customise their visual experience for better comfort during prolonged use.

Suggest two advantages of using robots, instead of humans, to build cars in the factory.

  • more efficient than a human
  • more accurate than a human
  • can lift larger and heavier equipment than a human
  • can replace humans working in a dangerous environment
  • reduces running costs, such as wages and overheads
  • can produce consistent results/output
  • can work 24 hours a day // do not need to take breaks.

 

State what is meant by each of the following modes of data  processing

(i) Batch processing.
(ii) Real-time processing.
(iii) Online processing.
(iv) Off-line processing.

(i) Jobs collected together for processing at a later time
(ii) Output produced quickly enough to affect the next input
(iii) User has direct contact with the processor
(iv) User cannot communicate directly with the processor

A company making televisions has introduced robots to replace the human work force.

(a) Describe three effects this would have on the work force

(b) Give two advantages to the company of introducing robots

(c) How could the robots be trained to assemble the televisions?

(d) A whole batch of televisions was produced with some of the parts missing. How could this error have been avoided?

(a) Describe three effects this would have on the work force

  • loss of jobs/unemployment
  • deskilling
  • need to re-train
  • different jobs available/re-skilling
  • no longer need to do hazardous/tedious jobs

(b) Give two advantages to the company of introducing robots

lower work force costs (no salaries to pay)

  • lower environmental costs (less electricity for heating/lighting)
  • higher throughput
  • more consistent product
  • robots don’t need breaks, holidays/work 24/7 etc.
  • robots don’t take industrial action

(c) How could the robots be trained to assemble the televisions?

  • tasks repeated by skilled worker and how each task is done is memorised
  • tasks programmed directly into the computer/robot memor

(d) A whole batch of televisions was produced with some of the parts missing. How could this error have been avoided?

  • if parts missing for a sequence, then a warning should be given and the assembly stopped
  • several quality control stages to spot an error early on
  • program in checks at each stage of assembly so robots can detect a fault immediately

Describe the principles of operation of  laser printers and describe how they are applied in real-life scenarios

  • A laser printer makes use of powdered ink and static electricity to print
  • Unlike inkjet printers which print line-by-line, laser printers print the whole page in one go

Steps

  • The data from the  file to be printed is sent to a printer driver
  • The printer driver checks that the data is in an understandable format
  • The printer driver checks if the printer is able to carry out the print job
  • The data is sent to the printer and is stored in a printer buffer
  • A printing drum in the printer is given a positve charge. A laser beam removes the positive charge in some areas. This leaves negatively charged areas which matches the characters/images to be printed
  •  

Briefly describe the following

Multitasking - the  capability of an operating system to enable users to run two or more programs at once on a single computer

Real time processing - data processing system in which the time interval required to process and respond to inputs is so small that the response itself is useful for controlling the physical activity of a process

Time-sharing processing  - a processing mode in which the central processor serves two or more users with different processing requirements (tasks)

On-line processing - is that type of processing where the result of data processing transaction is available immediately

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.

5 Artificial intelligence is an emerging trend in computer science.
(a) Discuss the use of artificial intelligence by describing some of its characteristics, the ways in which it may be used and the ethical issues associated with its use.
 

Branch of computer science based on enabling computers to
behave like humans/mimic aspects of human intelligence
AI is implemented in software.
Combines psychology, biology, linguistics, mathematics, neuroscience,
and philosophy (ethics)
AI is not the same as the general intelligence of human beings

 

Uses – Any of the following:
Game playing (chess, quiz, video games)
Analytics (analyse buying patterns, predicting behaviours, predictive
text, financial markets)
Image processing (recognising objects/patterns)
Logistics (scheduling, order fulfilment)
Control systems (cars, manufacturing, weapons, navigation)
Expert systems (medical, mechanical, electrical diagnosis)
Neural networks (simulating neuron behaviours as in brains)
Natural languages processing (chatterbots, chatbots, speech
recognition)
Robotics (dangerous situations, help aged or disabled)

 

Ethical issues – Any of the following:
Take the work of humans, thereby affecting employment rates
Is a computer to be trusted to make decisions (life-death)?

If a computer discovers something that humans can’t prove, should it be
accepted as truth?
Do AI machines have rights?
Will people be comfortable interacting with machines that are
considered intelligent?

What is block operation as used in Microsoft word?

An editing or formatting procedure that is carried out on a selected block of text in a word-processing document.

A formatting or editing operation that is applied to a block of text after selecting. The block of text can be a paragraph, line, word, page or the whole document. It is much easier to apply editing or formatting to a block of text than to apply it to every single character

Describe a typical situation that requires the use of:

(i) a high-level language

(ii) a low-level language.


High level languages are used in situations when:

  1. Speed of execution is not a critical factor, such as in office applications.
  2. a programmer needs to use complex commands that perform complex tasks.
  3. A programmer wants to make use of standardised library / sub routines.

Low level languages are used in situations when:

  1. a program must execute quickly such as real time applications
  2. a programmer needs to write code that interacts directly with the hardware, such as device drivers
  3. a programmer needs to perform a specific command not available in a HL language.

Distinguish between real-time and distributed operating systems (KCSE 2018)

  • Real-time OS reads information from input devices and must respond within a short duration of time to ensure correct performance
  • Distributed OS distributes computation among several physical processors which do not share memory or clock

Name four data management tools used in spreadsheets. (2 marks)

- Filtering - Sorting - Input validation - Subtotals - Data entry forms

State three types of optical disks

  • compact disks
  • DVDs
  • Blue Ray

When developing a network security policy, it is important to understand the threats that can be made against a network. ‘IP spoofing’ and ‘back doors’ are two techniques that can compromise the security of a network. Describe each of these techniques.

IP spoofing

A technique used to gain unauthorised access to a computer whereby an intruder sends messages to that computer from a false IP address

Back door:
An undocumented method of gaining access to a program, online service or an entire computer system

Describe overtype and insert modes as used in word processors

  • Overtype mode: deletes the current text at the cursor position and replaces the existing characters with new text
  • Insert Mode: pushes the existing text away as new text is inserted between the existing text