KCSE Revision Resources

State the primary function of the Dynamic Host Configuration Protocol (DHCP) protocol.

it generates and/or allocates an IP address

List three characteristics of Internet Protocol version 6 (IP6).

has a significantly larger address pool than previous version

features a client-side address assignment

has built-in encryption

enables one device to have many network addresses

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.

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.

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

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

Explain, with examples where appropriate, the following five computer terms.

(a) Buffer

(b)batch processing

(c) e-commerce

(d) simulation

(a) Buffer

temporary storage or memory which compensates for the difference speed of peripherals and the CPU

(b)batch processing

processing doesn’t start until all data is collected
JCL (any reference to Job Control Language)
no need for user interaction
processed all in one go
done at “quiet” times
e.g. billing, payroll, cheque processing

(c) e-commerce

electronic commerce
buying and selling products/services using the internet/computer networks

(d) simulation

studying the behaviour of a system by using a model/mathematical representation
results can be predicted
e.g. flight (or other) simulator, modelling hazardous chemical process

(e) Email

sending messages from one device to another using computer networks/Internet

Describe three possible threats to the computers connected to the network and give one way each threat can be reduced or prevented

Virus / trojan / worm / malware

Piece of software/code/a program that replicates itself or causes damage e.g. editing/deleting files

Prevention

Running anti-virus/anti-malware software
don’t download from unknown sources
don’t click on unknown links

Spyware / malware / keylogger

Piece of software/code/a program that records actions/key presses and sends this data to a third party analysis

Prevention

Running anti-spyware/anti-malware software/firewall

Data interception / passive

Data is sent to another device and is intercepted by a third party

Prevention

Encryption

Phishing

An e-mail has a link that when clicked directs the user to a fake website that collects personal data

Prevention

Network policy // firewall

Pharming

A piece of code installed that redirects user to fake website that collects personal data

Prevention

Anti-malware or firewall

Hacker

Person attempting to gain unauthorised access to the network/computers/ data/files
unauthorised access and then deleting/editing data/files

Prevention

Firewall
strong password
biometrics
penetration testing

Give two other uses of hexadecimal in computer science.

colour codes // colour in HTML/CSS

error messages

locations in memory

memory dump // debugging

IP(v6) address

ASCII // Unicode

assembly language

URL.

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.

A web server has an internet protocol (IP) address. Give three characteristics of an IP address.

consists of values between 0–255 / 0–FFF

values are separated by full stops/colons

it is a unique address

can be static or dynamic

can be public or private

can be IPv4 / have four groups of digits

can be IPv6 / have eight groups of digits

in IPv6 :: can replace groups of zeros.

Identify the network component that uses the IP address to send data only to its correct destination

Router

The website has a uniform resource locator (URL).
An example of a URL is given.
https://www.google.co.ke/index.html
Complete the table to identify the name of each section of the URL.

https : protocol

google.co.ke: domain name

/index.html: webpage/file name

State two advantages and one disadvantage of having a network of computers, rather than a series of stand-alone machines, in a school classroom.

Advantages

Sharing of software and data files
Sharing of hardware, e.g. printers
Communication

Disadvantages

Security of files is more of a problem

Identify the protocol used to transfer data in networks.

TCP/IP

Below is a labelled diagram of a star topology network.

(a) Other than the items labelled above state the hardware required by every computer to connect to a network

b) Describe how a packet is transmitted from computer A to computer D, including the role of the switch

(a)

Hardware required by each computer to connect to a network is a Network Interface Card / NIC / network adapter

(b)

Computer A adds computer D’s address to packet
Computer A sends packet to switch
Switch looks at address on packet Switch compares to stored list of addresses on network
Switch forwards packet to computer D’s address

State the function of a switch in a computer network

It transfers data signals from one node directly to another in the network without broadcasting

State five functions of network operating system

allowing the network to share resources like files and software for printers and computers

support the network's implementation of security features

controls user accounts

supplies network administrators with network monitoring tools.

State email protocols

Simple Mail Transfer Protocol (SMTP)

Post Office Protocol (POP)

Internet Message Access Protocol(IMAP)

Many organisations provide free public access to a wireless network.
Explain three ethical, legal or data privacy issues that an organisation should be aware of when allowing this access

Websites – any inappropriate websites ie pornography, drugs, guns,

terrorism etc. e.g. is it acceptable for the organisation to allow access to this

sort of material when you can’t control who is accessing the service?

Time – limit amount of time, they may not want to provide indefinite access

or may want to charge for access after the time limit has expired.

Preventing file sharing and illegal sharing\use of copyrighted materials.

Accountability – identification of users and actions on a network by

preventing anonymous access.

Prevention of illegal activities such as terrorism and fraud.

The responsibility to keep children safe and protected.

Responsibility to keep users (customers) data safe and secure.

Spoofing of websites, phishing. Responsibility of organisation to put some kind of protection in place, eg filtering of known fraudulent sites.

Recording of private messages or details if not encrypted.

Recording of usernames and passwords that the user may also use to access other systems.

Responsibility of organisation to secure their systems from possible attack.

Sales and marketing – providing sales leads to market products.

Q&A-KCSE Computer Studies Paper 1

DOWNLOADS:KCSE & JOINT EXAMS

Q&A CRE

Q&A History

Maths Topical

Q&A Sciences

Q&A Mathematics

Q&A Geography

Q&A Computer Studies

Q&A Category

Related Content

Get in Touch

Useful Links

Quick Links

External Links