State two ways of protecting computers against viruses.
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
Describe what is meant by a MAC address.
State two components of the CPU
Any two from:
State three utility programs associated with the use of a hard drive. Explain the purpose of each the program
Describe how the database can be recovered from a system failure
451/1
COMPUTER STUDIES
PAPER 1
THEORY
DECEMBER 2021
TIME: 2 HOURS
FORM TWO END OF TERM TWO 2O21 EXAM
451/1
COMPUTER STUDIES
PAPER 1
THEORY
TIME: 2½ HOURS
INSTRUCTIONS TO CANDIDATES:
Explain the difference between the sequential and parallel computational models.
Any four of:
Sequential:
• Individual instructions are executed one after another
• Flow control is accomplished by jump/branch/goto instructions
• Results are usually achieved less quickly than parallel processing (do
not award twice)
Parallel:
• Individual instructions can be routed to different processors for
simultaneous execution
• Results are usually achieved quicker than sequential instruction (do not
award twice)
• Requires multi-core processors or multiple microprocessors
• Tasks may be split into different parts with each part executed on a
different processor
• Results need to be merged back together after completion
Describe two different functions performed by an operating system
Memory management
Processor management
Input/output management
Managing storage
Managing security
Managing applications
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
(b) Give two advantages to the company of introducing robots
lower work force costs (no salaries to pay)
(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?
Describe what is meant by a clock speed of 3.8 GHz.
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;
List four ways of acquiring software in an organization
Commercial off-the-shelf (COTS) software: Organizations can purchase pre-developed software solutions from commercial vendors. These software products are typically ready-made and designed to fulfill common business needs. Examples include productivity software, customer relationship management (CRM) systems, and accounting software. COTS software can be licensed based on a one-time purchase or a subscription model. Custom software development: Organizations may choose to develop custom software tailored to their specific requirements. This involves hiring software developers or outsourcing the development work to a third-party vendor. Custom software offers flexibility and can be designed to align with unique business processes and workflows. It allows organizations to have full control over the software's features and functionality. Open-source software: Open-source software is developed collaboratively and made freely available to the public. Organizations can acquire open-source software without incurring licensing costs. They have the right to use, modify, and distribute the software as per the terms of the open-source license. Open-source software can be an economical option, and it allows organizations to benefit from community-driven development and ongoing improvements. Software as a Service (SaaS): SaaS refers to software applications that are accessed and used over the internet. Organizations can acquire software on a subscription basis, where the software is hosted and maintained by the vendor. Users access the software through web browsers or dedicated client applications. SaaS eliminates the need for local software installation and offers scalability and accessibility from any location with an internet connection.
Explain the purpose of each of the following features of a spreadsheet chart (KCSE 2021, Q19 (a))
A data series
Data Marker
Legend
A data series
Data Marker
Describe the role of the registers and system clock within the fetch-execute cycle.
Give one benefit and one disadvantage of the use of wireless technology.
Advantages
disadvantages e.g.
Give one example of wireless technology
method of transmission e.g
device e.g.
Describe one difference between system software and application software
What precautions would you take in a computer room in case a user complains of backache after long periods of using the computer?
Ergonomic Chair: Ensure that each user has an ergonomic chair that provides proper lumbar support. The chair should be adjustable in terms of height and backrest angle. Adjustable Desk: Provide adjustable desks or workstations that can accommodate different user heights and allow for proper positioning of the keyboard, mouse, and monitor. Monitor Placement: Ensure that the computer monitors are positioned at eye level or slightly below to prevent users from straining their necks and shoulders. Consider using monitor stands or adjustable monitor arms for better positioning. Keyboard and Mouse: Encourage the use of ergonomic keyboards and mice that are designed to minimize strain on the wrists and hands. Provide wrist rests if needed. Proper Lighting: Ensure that the computer room is well-lit, with appropriate lighting levels to reduce eye strain. Avoid glare on the computer screens by using adjustable blinds or curtains. Regular Breaks: Encourage users to take regular breaks from prolonged computer use. Suggest the 20-20-20 rule: Every 20 minutes, look away from the screen at an object 20 feet away for at least 20 seconds. Stretching Exercises: Promote stretching exercises for the neck, shoulders, and back to help alleviate muscle tension and improve blood circulation. Display posters or provide resources on desk stretches and exercises. Correct Posture: Educate users about proper sitting posture, emphasizing the importance of maintaining a neutral spine position. Provide visual aids or ergonomic training materials to demonstrate the correct posture. Desk Organization: Encourage users to keep their workstations organized to minimize the need for reaching or straining. This includes keeping frequently used items within easy reach and arranging cables to prevent trip hazards. Individual Assessments: If the backache issue persists, consider offering individual ergonomic assessments for users. A specialist can evaluate the user's workstation setup and suggest personalized recommendations.
Identify one component common to all computers.