Kagumo High School Computer Studies Paper 1 2024

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COMPUTER STUDIES

PAPER 1

MARKING SCHEME

State any three differences between data and information. (3 Marks)

Versatile- Computers are flexible in that they can be used to carry out different types of activities such as typing, calculations and playing music.

Reliable – Computers are more reliable because they do not get tired or bored in the processing repetitive activities

State any three types of computer programme documentation

-User oriented

-Operator oriented

-Programmer oriented

List the steps that you would use to correct wrongly spelt words in a document using the spell-checking feature.(3marks)

Make sure automatic spelling and grammar checking are turned on.

Type in the document.

When the spelling checker encounters a word it doesn't recognize, it determines the words in its dictionary that are similarly spelled and displays a list of those words with the most likely match highlighted.

Right-click a word with a wavy red or green underline, to get a list of correct alternative words to choose from.

From the list, click the correct command or the spelling alternative you want.

Award ½ mark each, maximum of 3marrks

With an aid of a diagram, differentiate between selection control structure and iteration control structure.

Selection(4 marks)

LOOPING

Name any two types of graphs that are supported by spreadsheets  (2marks)

Bar graph

Line graph

Pie chart

Column graph

7. a) Distinguish between autocomplete and the autocorrect feature

Autocomplete is a feature that automatically displays a complete word when the user types the first few characters.

Autocorrect is a feature that automatically detects wrongly capitalized or spelt word and replaces it with the correct one.

(first 1x2)

b)What is thesaurus?

A tool that helps the user find words or phrases with similar meaning or opposite meaning to the one selected (first 1x1)

8. Auki company is in the process of computerizing its services. List four measures that should be put into consideration to protect the users in their computerized areas.(2 marks)

Power cables should be insulated

Providing standard furniture

Proper ventilation

Painting the wall with less reflective paints.

Overcrowding should be avoided.

Give two reasons why powder and liquid extinguishers are not recommended unlike gaseous extinguishers. (2 marks)

Liquid –based extinguisher may cause rusting and corrosion of computer components

Powder particles may increase friction, clogging and wearing of movable computer parts

9.State two advantages of using two’s complement. (2 marks)

Two’s complement has only one value for zero

The range of values represented by two’s complement is extended by one

(b) State any two characteristics of a computer infected by a virus(2 marks)

It is taking longer time to start up;

It is often hanging;

Applications are taking longer to load;

Unwanted random messages popping up;

Firewall disabled;

Reduced file size, encryption of files, loss of data etc.

10. Without proper marketing, a business cannot survive in a competitive environment hence computers are being used in a number of ways to enhance marketing. List any three ways of ensuring this is effected. (3 marks)

Electronic Commerce  or e-business

Electronic presentation

Advertising

11. Types of relationships as used in database design

3 x 1 = 3 marks

12.List down 3 similarities between a normal calculator and a computer. (3 marks)

Both have memory

Both accepts inputs

Both perform arithmetic calculations

Both display results

Fast

13.(a) The accounts department of a secondary school is using a system that generates invoices that are printed in triplicate using carbon papers.

Name one type of printer suitable for this task. (1mrk)

Dot matrix printer (character printer)

Daisy wheel printer (character printer)

Drum, chain or band printer. (line printers)

Give a reason for your answer I (a) above. (1mrk)

They are useful for low-quality carbon copy printing of text, or printing text on continuous sheets of paper.

(b) Identify three hardware considerations to be made before installing an operating system. (3mrks)

RAM capacity

disk space (memory capacity)

processor capacityand speed.

14.(a) State any two advantages and two disadvantages of an email over the Traditional Paper Mail/‘Snail Mail’ (4 marks)

Advantages of emails

It is very fast to communicate using emails.

It is almost free i.e. cheap

It is convenient to access from any internet enabled device anywhere anytime

Easy to send one mail to many recipients by use of carbon copies

Mail can be saved for future retrieval

Easy to send and reply mails. It doesn’t require a lot of training to browse.

Mails can easily be forwarded to another recipient

Document created using other application can easily be attached to the mail etc.

Reliable if all email etiquette and netiquette is observed.

Disadvantages of emails

Security of message may not be guaranteed – due to tapping while on transit.

Not yet accessible to everybody due to the connectivity limitations such as lack of infrastructure and the cost of calling being high.

Requires some ICT literacy to use and enjoy

It is boring to read ‘junk mails’ that are unsolicited as spam

15. Define Solid-state storage and give two examples. (2 marks)

A non-volatile storage that employ integrated circuits rather than mechanical, magnetic or optical technology. They are referred to solid state because they do not have movable parts in its read/write storage mechanism.

SECTION B (60 MARKS)

16. .a) state two qualities of a pseudo code (1 mark)

The statements must be short, clear and readable

The statements must not have more than one meaning

Pseudo code lines should be clearly outlined and indented clearly

The input, output and processing statements should have key words like Print, Read, Input

b) Explain two methods of testing the program for errors (2 marks)

Use of dry run method

Use of test data

Use of debugging utilities

The Figure below shows a flowchart. Use it to answer the questions that follow.

a) Interpret the flowchart  (7marks)

b) Write a pseudo code for the flowchart  (5 marks)

N=1

Base=21mark

Power 10

Ans=1

Ans=Ans*Base1mark

N=N+1

Display Ans

Stop ½ mark

17. (a) define the following terminologies as used in data representation.  (3mrks)

Word – these are two or more bytes or a group of bits that the computer recognizes and executes (processes) at a time.

Nibble – it’s a group of 4 bits. Half a byte

Byte – a group of 8-bits

(b)Complete the following table (9 marks)

( c) using two’s compliment, perform the following binary arithmetic leaving the answer in decimal notation. (use 8bits) (3mrks)

54 - 29

54 – 29 = (+54 )+(-29)

2 27 0 29 rem 11101 to ones compliment

2 6 1 2 7 0 convert to two’s compliment

2 3 0 2 3 1 11100010 + 1 = 11100011

2 1 1 2 1 1 ADD 00110110 + 11100011

54₁₀ = 110110₂29₁₀ = 11101₂overflow bit is ignored

18. (a) In order to generate information from data items, a set of processing activities have to be performed  on the data items in a specific sequence depending on the desired result. Draw a well labeled  diagram to illustrate data processing cycle.  (2 marks)

(b) A data entry clerk experiences some common errors when typing. Most of the time, she finds that:

After every calculation, the result is less than the expected number of digits required e.g. 345.7896543 the result is given as 345.789.

Different characters are typed wrongly, for example instead of typing 12873457 she types 128734S7.

Identify the two types of errors commonly experienced by the clerk during data processing in (i)  and (ii) above respectively. (2 marks)

Truncation error

Misreading error

(c) State two ways a user can ensure data accuracy is maintained during data processing. (2 marks)

Using modern data capture devices (direct data capture) such as barcode readers, optical character readers, digital cameras etc., which capture/enter data with minimum user involvement.

Design user interfaces that minimizes chances of invalid data entry.

Double entry checks

Use of error detection and correction software when transmitting and processing data.

Use of automated data verification and validation routines in the data processing system.

(d) (i) State three advantages of a computerized filing system as used in data processing. (3 marks)

information takes up much less space than the manual filing

it is much easier to update or modify information

it offers faster access and retrieval of data

It enhances data integrity and reduces duplication

It enhances security of data if proper care is taken to secure it.

(ii) State two disadvantages of a serial file organization method in computing. (2 marks)

It is cumbersome to access because you have to access all proceeding records before retrieving the one being searched.

Wastage of space on medium in form due inter-record gaps in storage.

It cannot support modern high speed requirements for quick record access.

(iii) Differentiate between distributed processing and interactive processing modes; stating one   application area of each. (4 marks)

Distributed:

Various geographically dispersed computers are linked by communication lines and all the computers linked belong to the same organization.

The computers are located at various departments or business sites for the individual departments or the business site to be served individually by its own computer resources.

All the branches have intelligent terminals (usually micro computers) linked to a big computer at the head office. Data from the branches is sent to the master where it is processed.

Interactive:

Occurs if the computer & the terminal user can communicate with each other.

It allows a 2-way communication between the user & the computer.

As the program executes, it keeps on prompting the user to provide input or respond to prompts displayed on the screen.

The user makes the requests and the computer gives the responses.

The data is processed individually and continuously, as transactions take place and output is generated instantly according to the request made by user.

19. (a) Define the following terms as used in networking.  (3marks)

Network

A collection 2 or more computers connected together using transmission media (e.g., telephone cables, or Satellites) for the purpose of communication and sharing of resources.

Intranet

Internal corporate network that uses the infrastructure of the Internet and the World Wide Web.

Browser

A browser (short for web browser) is a computer program/software that accesses webpages and displays them on the computer screen. It is the basic software that is needed to find, retrieve, view and send information over the internet.

(b) The World Health Organization is global entity that deals with health issues around the world. It has computer networks linking its regional and continental offices using internet. State two importance of the internet to such organization. (2 marks)

Communication with other organizations, with your members, with your staff, with your supporters and donors through e-mails, messenger, web pages, mail lists, web site message boards. The Internet greatly offers rapid communication on a global scale. It even delivers an integrated multimedia entertainment that any other mass medium cannot offer.

Publishing your message to the world using online books, journals, press releases, workshops, conferences, lectures. Websites with conference proceedings, PDF (Portable Document Format) files of your publications, blogs, newsfeeds e.t.c. support publishing.

Customer support - the people you are helping through your organization. It can help them when you aren't there: email, messenger, web pages, mail lists, and web site message boards. With video-conferencing, podcasting and other great web tools, you can even have workshops and classes online.

Research on news, issues, papers and literature relevant to your cause. Use of search engines to find materials world-wide, mail lists e.t.c.

Leisure activities – e.g. online games, videos or music.

A place to do business and many other commercial activities. E.g. e-bay, amazon.com, e.t.c.

(c) Mr. Zuma, the Principal of a school wishes his school to have an internet connection in a bid to improve its service delivery. Mention four internet connectivity requirements that must be present to enable the connection.  (2 marks)

Transmission/Telecommunication/Network media

Data Terminal Equipments - A TCP/IP enabled computer with a web browser.

An account with an Internet Service Provider (ISP).

Networking equipment such as a modem, router or switch to connect the computer transmission media.

(c) Explain the following as used in e-mail:

Inbox: Stores incoming mails (1 mark)

Drafts: Stores a saved copy of e-mails (usually composed but unsent) for later use.(1 mark)

(e) (i) Failure of information systems is a major concern in the security of data in computing systems. State two causes of such failure. (2 marks)

Hardware failure due to improper use.

Unstable power supply as a result of brownout or blackout and vandalism.

Network breakdown

Natural disaster

Program failure/crash

(ii) Explain the following computer crimes.

Fraud (1 mark)

Fraud is the use of computers to conceal information or cheat other people with the intention of gaining money or information.

Industrial espionage  (1 mark)

Involves spying on a competitor to get or steal information that can be used to finish the competitor or for commercial gain. The main aim of espionage is to get ideas on how to counter by developing similar approach or sabotage.

(f) Excluding passwords, state two other security control measures used to guard against unauthorized access to computers in a network. (2 marks)

Audit trails

Firewalls

Proxy servers

Log files/security monitors

Encryption

User access levels/Multilevel access

Biometric security

20. a) Explain why a computer is able to display the correct time and date when it has just be switched on.  (2mks)

Because it is set and stored in a special memory known as the complementary metal – oxide semiconductor

 (cmos) chip which is powered by cmos battery

b) Discuss two types of special memories found in computer system. (4 mks)

i)Cache – Fast type of RAM found in the processor.

ii)Buffers – Special memories found in the input / output devices.

iii) Register - Hold one piece of date at a time and are found in the ALU

c)i) Define a bus with reference to a computer system. (1 mk)

- Bus – This are electronic pathways or links

ii)List two examples of buses (2 mks)

i) Address bus ii) Data bus iii) Control bus

d) Distinguish between a power cable and interface cable. (2 mks)

- A power cable is used to transmit data from the source (socket) to the computer while interface cables are

special cables used to connect peripheral cables to the system unit.

e) Differentiate between the different types of RAM. (4 mks)

- Static RAM – is a fast type of RAM located inside the microprocessor

- Dynamic RAM – is a relatively slow type of RAM. It has the tendency for the stored charge to leak a way even with constant power supply hence requires periodic recharging.