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)
(b)
State the function of a router in a network
Why is 2's complement preferred over 1's complement?
Describe what is meant by shareware.
the trial version of software for a limited time/number of uses with limited features free of charge
If a full version is required need to pay a fee/sign up
When the trial is over user is asked to pay/sign up
Protected by copyright
Type of software licence
Give an example of where a PAN could be used
Describe two methods used to assist in finding program errors.
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.
Explain the functions of the following parts of the CPU
Control Unit; Decodes instruction; Controls the fetching and writing of data;
Arithmetic Logic Unit/ ALU; Executes mathematical instructions; Executes logical instructions; Compares values held in registers;
Clock; Controls the number of instructions carried out each second; allows the CPU to synchronize operations;
Give one example of wireless technology
method of transmission e.g
device e.g.
Give two reasons why hexadecimal is often used instead of binary in computer
science.
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
(b) The computer needs an operating system and utility software.
(i) The operating system controls the scheduling of processes.
Describe how the operating system uses scheduling to allocate processor time.
A virus is a specific category of malware. Describe three other different categories of malware.
Trojan (horse); a program which misleads the user into thinking it is another
piece of software which, when run, executes another program;
Spyware; a program which records data such as usernames and passwords on
a host system and forwards the information to a third party;
Adware; code embedded or attached to program files which will persistently
show adverts (that attempt to generate revenue);
Worm; code which will run autonomously and replicates itself on a host system;
Ransomware; a program that encrypts a user’s data to make it unreadable until
they pay for the key;
Remote Access Tool (RAT); allows access to control and monitor a computer
from a remote network location;
Rootkit; malware that has managed to gain ‘root’ admin privileges;
Bots/Zombies; a program installed on a computer that performs a job for the
remote owner of the bot/zombie such as sending spam or sending web requests
to perform a DOS or attack a computer system;
Scareware; malware that tells you something is wrong with your system in an
attempt to get you to make a purchase;
Keylogger; a program that monitors/records a user’s keystrokes in order to steal
passwords/confidential details
List three types of errors that are likely to exist in a program (3 marks)
Syntax errors-Incorrect use of programming language
Logical errors- The program do not give the expected output
Runtime errors- Premature end of a program
Define the following terms as used in the internet
HTTPS/HTTP: this is a protocol that is used to send data to web pages across the Internet
Uniform Resource Locator (URL): a text-based version of a web address
Internet Service provider /ISP - his is the company that provides a user with a connection to the Internet
browser - Software/application that allows users to view web pages / render HTML -
cookie - a text file (stored by a web browser) that contains data about a user’s browsing habits/details/preferences
Give one application of each type of data transmission. Each application must be different
Parallel
Serial
Explain two computer hardware features that may be considered when selecting a laptop computer to be used in developing a KCSE computer studies project (4mks)
Multimedia Capability - A laptop with strong multimedia capabilities is essential for a computer studies project submitted on CD-RW. This ensures that the laptop can efficiently handle multimedia content, providing a seamless experience in creating and presenting project materials.
Processor Speed - Opting for a laptop with a high processor speed is crucial. This feature enables the smooth execution of multiple applications simultaneously, enhancing overall project efficiency and reducing processing delays.
Hard Disk Capacity - Consider a laptop with ample hard disk capacity, as the Microsoft Office suite used in computer projects requires significant space for the installation and storage of project files. A spacious hard drive ensures that there is sufficient room for data and applications.
Main Memory Capacity - Given that students often work with multiple programs concurrently during a project, it's important to choose a laptop with an adequate main memory size. A smaller main memory may result in performance issues, hindering the seamless operation of various software applications during project development.
Give two benefits for the supermarket manager of using point of sale (POS) terminals.
Explain one reason why a computer needs to be connected to a stable power source
System Stability: Computers require a consistent and stable power supply to function properly. Fluctuations or interruptions in the power source can cause various issues that can disrupt the computer's operation or lead to hardware damage.
a. Data Loss: Sudden power outages or voltage fluctuations can cause the computer to shut down abruptly, resulting in data loss if unsaved work is not properly stored. This can be particularly problematic when working on critical tasks or handling important files.
b. Hardware Damage: Power surges or inconsistent power supply can damage the computer's internal components, including the motherboard, CPU, memory, and storage devices. These damages can result in system instability, reduced performance, or even complete hardware failure.
c. Operating System Corruption: Abrupt power loss or inconsistent power supply can corrupt the operating system files, leading to system crashes, error messages, and instability. This may require system repairs or reinstallation of the operating system.
d. Component Lifespan: Inconsistent power supply can put unnecessary stress on computer components, shortening their lifespan. Frequent power fluctuations or surges can cause wear and tear on various parts, reducing their efficiency and overall longevity.