Download Introduction to Computer Fundamentals: KCSE Notes and more Cheat Sheet Computer science in PDF only on Docsity!
About the book
Education is a key for a country’s development, but it becomes a hindrance when it is unequally
distributed. This big problem of disparity in Education system can be solved through technology.
Hence it’s high time we embrace technology in Education sooner than later.
Teachers will therefore use the book in their laptops to teach and even give students notes to read
online after revision.
The design of this book make it lively and interesting for both teachers and students as it take us
away from the monotony of black and white books. The book is divided into two parts: Theory
and Accounting.
We have past K.CSE questions at the end of every topic for further understanding and testing.
For free KCSE Notes, Exams, and Past Papers Visit https://Teacher.co.ke/
CHAPTER ONE
Specific Objectives
By the end of the topic the learner should be able to:
a) State the different parts of a computer; b) Explain how computers have developed; c) Classify the various types of computers; d) State the safety precautions and practices in a computer laboratory: e) Demonstrate basic hands-on-skills on the use of a computer. Content a.) Definition of a computer b.) Parts of a computer c.) Development of computers d.) Classification of computers
- Physical Size
- Functionality
- Purpose e.) Areas where computers are used f.) Definition of a computer laboratory g.) Safety precautions and practices in a computer laboratory
- Behavior
- Handling of materials and equipment
- Fire
- Cabling
- Stable power supply
- Burglar proofing
- Ventilation
- Lab layout
- Dust/damp control
- Lighting
- Standard furniture h.) Hands-on skills
- Start-up
- restarting and shut-down (Booting)
- Keyboard layout
- Practical keyboard and mouse skills
INTRODUCTION TO COMPUTERS
For free KCSE Notes, Exams, and Past Papers Visit https://Teacher.co.ke/
Classification of Computers
- Size and Memory
- Purpose
- Functionality
Classification according to Size and Memory
i. Supercomputer ii. Mainframe iii. Minicomputer iv. Microcomputer v. Desktop vi. Laptop vii. Palmtops
Advantages of laptops
Portable Ruggedness: Designed to withstand travelers Display active color screen Power batteries serve as ups
Disadvantages
Less expansion options They are easily stolen
Classification according Purpose
1. General computers This computer can do or handle a variety of tasks when loaded with appropriate programs. 2. Special computers They are designed to serve a specific purpose or to accomplish one particular task. 3. Dedicated Computers They can handle any task but it is a dedicated to one task.
Classification according to Functionality
- Digital computers: They handle discrete data.
- Analog computers: Deals with data that keeps on changing in time (Continuous data).
- Hybrid computers: The computers can handle both analog and digital data.
Elements of a Computer System
- Input: Data or raw facts.
- Processing: Act of transferring raw facts into meaningful output or information.
- Output: Processed data or information. 4. Storage:
For free KCSE Notes, Exams, and Past Papers Visit https://Teacher.co.ke/
Control unit:
Functions of the control unit are- Avails instructions in sequence Interprets instructions Initiates the appropriate actions thereby controlling all the processes
Development of Computers
First Generation Computers (1940 - 1958) Used thermionic valves or vacuum tubes Advantages Vacuum tubes technology made it possible with advent of electronic digital computers It was the fastest calculating device that time. Disadvantages Too bulky Unreliable Had limited memory Generated a lot of heat Consumed a lot of power Examples IBM 650, UNIAC
Second Generation Computers (1958 – 1964)
They used transistors Advantages Smaller than first generation computers More reliable Generated less heat than the first generation Less prone to hardware failure
Disadvantages Required air condition for cooling Required frequent maintenance It was very expensive Examples IBM1401, Honeywall200, CDC1604 e.t.c.
Third Generation Computers (1964 – 1970)
They used Integrated Circuit (IC) Advantages Smaller in size More reliable than the previous ones
For free KCSE Notes, Exams, and Past Papers Visit https://Teacher.co.ke/
Areas where Computers are used
- Supermarkets: Used to keep in stock control i.e. keep accounts of what is in the store, what has been sold, what is out of stock e.t.c
- Offices: First access and receiving information, automate faster message distribution and document processes.
- Banks: Special cash dispensing machines called Automated Teller Machine (ATM for cash withdrawal and deposition service. They provide better record keeping and document processing.
- Industries: Monitoring and controlling industrial processes e.g. using robots
- Hospitals: Keeping patients records for easier access to treatment and diagnosis. Computerized diagnosis in laboratories.
- Communication: Sending and receiving emails, teleconferencing, telecommuting, facsimile and e-calling.
- Transport: Monitoring automobile traffic, aircraft navigation and making flight reservation.
- Law enforcement Biometric analysis- study of human biological characteristics to know fingerprints, voice and facial features. Video cameras e.g. in banks. Development of strong military bases which have international coordination by use of computer radar. Jet fighters are computerized with connection to control centres.
- Education: Computer Aided Learning (CAL) and Computer Aided Teaching (CAT).
- Domestic and entertainment/ home: used at home for recreation purposes and keeping budgets.
- Library services: Easy access and update of books and other library materials.
Advantages of a Computer
Stores large amount of information in a limited space Speed: performs tasks in very short periods. Efficiency: creates an all round saving on space and time. Consistency: gives the same results given the same data and instructions. Secrecy: information is fairly protected if computer system is well managed. Versatility: Can do the same thing over and over again without being worn out.
Disadvantages
Computers are very expensive Cuts down employment opportunities Needs expertise which is expensive to hire and maintain They create eye problem
For free KCSE Notes, Exams, and Past Papers Visit https://Teacher.co.ke/
Loss of information if not well managed.
Computer Laboratory, Safety Precautions and Practice
Considerations for a Computer Laboratory
- The number of computers to be installed.
- Size of the laboratory.
- The number of user that the laboratory can accommodate.
- Reliability of a source of power.
Safety Precautions and Practices
- Behavior in Computer Laboratory Avoid smoking or exposing computer to dust. Smoke and dust damage computer components. Avoid carrying food and beverages: may damage components and liquids may cause rusting and electrical shocks. Avoid unnecessary movement because you may accidentally knock down peripherals. Follow the correct procedure for storing and shutting down computers. Reporting accidents immediately. Ask for assistance.
- Ventilation: to avoid suffocation and overheating. This avoids damage of electronic parts.
- Lighting: to avoid eyestrains that leads to headaches, stress and fatigue. User may adjust brightness of computer monitor. Also radiation filter screen may be fitted.
- Protection against fire: Use or fit gaseous fire extinguisher.
- Dust and dump control Special curtains reduce dust entry Covering computers
- Regulate humidity to remain at an optimum of 50%.by the use of humidifier and dehumidifier. Low humidity allows static electricity to build up and cause damage to computer components. High humidity causes corrosion, destroy devices and electrical faults.
- Furniture: Strong and wide enough to accommodate all peripheral devices. User seats must be comfortable and have straight back rest that allows someone to sit upright to avoid muscle pains and aches.
- Burglar proofing: Fit strong metallic grills and locks on doors and windows Don’t welcome strangers to computer room Install security alarms at strategic access points to alert security personnel incase of break in.
- Stable power supply: Functions of Uninterrupted Power Supply (UPS)- Regulate high voltage Regulate low voltage Provide temporary power Notify when power goes off.
For free KCSE Notes, Exams, and Past Papers Visit https://Teacher.co.ke/
Did you understand everything? If not ask a teacher, friends or anybody and make sure you understand before going to sleep!
Solved KCSE Questions on the topic
- (a) Clearly define a computer
- A computer is an electronic device that operates (works) under the control of programs stored in its own memory unit
- An electronic device that accepts data, as input and transforms it under the influence of a set of special instructions called programs, to produce the desired output (referred to as information)
(b) Give one reason why a computer is refered to as an electronic device
- It uses electrical signals to process data
- It is made up of electronic components and uses electric energy to operate
- Explain the following terms as used in computer science (i) Data A collection of raw facts, figures or instructions that do not have much meaning to the user
(ii) Program A computer program is a set of related instructions which specify how data is to be processed A set of instructions used to guide a computer through a process
(iii) Data processing It is the process of collecting all terms of data together & converting them into information
(iv) Information Data which has been refined summarized & manipulated in the way you want it, or into a more meaningful form for decision- making
- State any three functions of a computer
- Accepting data
- Processing the data
- Producing information
- Explain the following input/ output terms as used in computer systems. Give an example for each (a) Read - To transfer data from an input device to the computer, e.g. the computer reads data from a disk, a keyboard, etc
For free KCSE Notes, Exams, and Past Papers Visit https://Teacher.co.ke/
- To move or copy data from backing storage to the main Storage (b) Write - To transfer information from the computer to an output Device e.g. the computer writes output on a printer or onto a disk.
- To move or copy data from the main storage to a backing storage
- State four different parts that make up a computer (2 mks)
- System unit
- Monitor
- Keyboard
- Mouse
- Printer
- Modem
- Scanner
- Speakers
- Graph plotters
- (a) Explain the term system Unit This is the casing that houses the internal components of the computer such as the CPU and storage devices
(b) List four devices located under the cover of the system unit
- Central processing Unit (CPU)
- Motherboard
- Power supply unit
- Main memory
- Hard disk
- Disk drives
- Battery
- Buses
- Input/ output ports
- Video card
- Expansion slots
(c) Give two differences between tower – style and desktop system units
- Tower style system unit is designed to stand alone or to be placed on the floor, desktop units lie on the desk with the monitor placed on top
- Tower style units have more space for expansion than the typical desktop units (2 mks) 7. Computers have evolved through a number of generations. List any 4 characteristics of the first generation of computers.
- Large in physical size
- Relied on thermionic valves (vacuum tubes) to process and store data
For free KCSE Notes, Exams, and Past Papers Visit https://Teacher.co.ke/
- They were small & very fast
- Had storage (memory) capacity
- Magnetic disks, bubble memories & optical disks were used for storage
- The first operating system was introduced
Fifth generation computers
- Are the modern computers
- Are designed/ constructed using parallel architectures, 3 – D circuit design & superconducting materials
- Are very powerful, with very high processing speeds
- The computers can perform multiprocessing
- Have virtually unlimited ( very high) memory sizes
- Can support complex programs
- Use advanced hard disks and optical disks for storage, e.g. DVDs
- Use of zip disks
- Use of multi user operating systems & advanced application programs 9. State four factors used to classify computers
- Physical size & processing power
- Power
- Functionality (mode/ method of operation)
- Type of processor (CPU) 10. State the differences between desktop computers and laptop computers
- Desktop is designed to be used when placed on a desk in an office environment. A laptop can be used comfortably when placed on the User’s lap
- A laptop is small & portable; desktop computers are not portable 11. (a) Explain the emerging trends in microcomputer technology in relation to size
- PCs are becoming small and portable, e.g. personal Digital Assistant (PDA).
(b) Give two reasons why smaller computers like Laptops tend to be more expensive than Desktop computers
- The technology of producing smaller devices is expensive
- They are convenient because they are portable
- They have advanced power management capabilities (they consume less power since a laptop can operate on rechargeable batteries 12. Which category of computers would you place an N- series Nokia phone
- Microcomputer/ palmtop 13. Give three reasons why a mobile phone is regarded to be a computer
- It is electronic * uses electric energy to operate
- It has a display unit (screen)
For free KCSE Notes, Exams, and Past Papers Visit https://Teacher.co.ke/
- It has a keypad
- It has a memory for storage
- It is programmable 14. (a) Mention three Analogue devices
- Computer used to control a flight Simulator for training pilots
- Bathroom scale
- Thermometer
- Speedometer
- Post- office scale
- A radio with a knob that slides in a slot to increase volume
(b) Give three example of special – purpose computers
- Robots
- Mobile phones used for communication only
- Calculators that carry out calculations only
- Computers used in digital watches & in petrol pumps
- Computers used in petrol pumps
- Computers used in washing machines
- An automatic pilot
- A word processor 15. State a specific example where each of the following types of computers can be used (a) Supercomputer
- Weather f o recasting
- Petroleum research
- Defense and weapon analysis
- Aerodynamic design and simulation
(b) Mainframe computer ( 1 mk)
- Banks for preparing bills, payrolls, etc
- Hospitals
- Airports (i.e., in Airline reservation systems for booking & storing flight information)
- Communication networks as servers
(c) Minicomputer (1 mk)
- Scientific laboratories & research institutions
- Engineering plants for controlling chemical or mechanical processes
- Space industry
- Insurance companies & banks for accounting purposes
- Communication centers as servers
(d) Microcomputer / personal computer (1 mk)
- Training & Learning institutions, e.g. schools
For free KCSE Notes, Exams, and Past Papers Visit https://Teacher.co.ke/
- Entertainment e.g. watching movies, playing music, playing computer games
- For storing personal information/ documents
- For calculating & keeping home budgets Industries
- To monitor and control industries processes through the use of robots
- For management control, i.e. to keep track of elders, bills and transactions
- For advertisement purposes, which enable an industry to attack more customers Police stations
- Matching, analyzing & keeping databases of fingerprints
- For taking photographs & other identification details
- For record keeping
- For face recognition, scene monitoring & analysis which help the police carry out criminal investigations speedily Transport industry
- Airports; to control the movement of aircrafts, their take off & landing using radar equipment
- For making reservations (booking purposes)
- Storing flight information
- Automobile traffic control; to monitor vehicle traffic in busy towns
- In Railways corporations; to coordinate the movement of goods & wagons
- In shipping control, for efficient management of fleets, cargo handling & communication Offices
- For receiving & sending of information through e- mails, fax, etc
- Production of documents
- Keeping of records 19. Identify three advantages of using computers in banking (3 mks)
- Speed and accuracy
- Easy to access information
- Easy to update records
- Requires less space for storage
- Improves data security and privacy 20. (a) Define the term ‘ computer laboratory’ ( 2 mks)
- A computer laboratory is a room that has been specially prepared to facilitate installation of computers, and provide a safe conducive environment for teaching & learning of Computer studies. (b) Give two factors to be considered when preparing a computer laboratory (2 mks)
- Security of computers
- Reliability of the source of power
- Number of computers to be installed and the amount of space available
For free KCSE Notes, Exams, and Past Papers Visit https://Teacher.co.ke/
- The maximum number of users that the laboratory can accommodate 21. List down three safety precautions one should observe when entering a computer laboratory (3 mks)
- Avoid smoking or exposing computers to dust
- Avoid carrying foods & drinks/ beverages to the computer room
- Avoid unnecessary movements as you may accidentally knock the peripheral devices
- Only authorized people should enter the computer room
- Computers users should be trained on how to use computers frequently
- Computer illiterates should not be allowed to operate the computers
- collect any waste papers which might be lying in the computer room & put them into the dustbin
- Shut the door of the computer room properly 22. Describe the ideal environment for a computer to work properly (3 mks)
- Should be free from dust, water and magnets
- Should be kept in well ventilated rooms with optimum (medium) humidity 23. Explain why smoke and Dust particles are harmful to a computer
- Dust and smoke particles settle on storage devices and may scratch them during read/ write operation
- It affects the cooling of the computer 24. Identify three facilities that will ensure proper ventilation in a room
- Large & enough windows and doors
- Installing fans
- Installing air conditioning system
- Avoid overcrowding of either machines or people in the room 25. Why must foods and beverages be kept out of the computer room?
- Food particles may fall into the moving parts of the computer and damage them. Liquids may spill into the computer parts causing rusting or electrical faults 26. Why would it not be good to install Powder or Water – based fire extinguishers in the computer room?
- Powder particles settle on storage devices and may scratch them during read/ write operation
- Water causes rustling of metallic parts and short – circuits if used 27. (a) State one reason why a computer needs to be connected to a stable power supply (1 mk)
- To prevent damage to the computer’s secondary storage media
- To avoid damage and loss of important data or information such as application software stored on the media
- Prevent loss of data/ information that had not been saved before the failure
For free KCSE Notes, Exams, and Past Papers Visit https://Teacher.co.ke/
of important data.
33. List three things that can spoil a printer if they are not of the correct specification, and explain what damage may be caused (i) Printer Paper: Different printers have different sensitivity to printing papers. Using the wrong quality paper in a particular printer can make the paper get stuck (ii) Cartridges & Ribbons: Printers are very specific to manufacture’s cartridges & ribbons Use of clones or imitations ( i.e., the wrong make & model) can damage the printer mechanism (iii) Refilling of cartridges or re- inking of ribbons: It can spoil the printer due to leakage or use of poor quality materials 34. Explain three ways that computer technology could make office more efficient (3 mks)
- There is easier & faster retrieval of data, i.e. they reduce the time and effort needed to access and retrieve information
- Increased accuracy of data
- Better presentation of data
- Ensure faster processing of data
- Ensures economic use of storage space 35. (a) Explain the steps you would follow to set up a new computer
- Gently and carefully connect the interface cable of each device to the correct port and to the device.
- Connect the computer to the source of power and switch it on.
- Observe boot up information on the screen to see whether Power-On Self Test (POST) displays any error message. A successful boot means that the computer was properly setup. (b) Outline three reasons why it is important to first shut down the computer before turning it off
- To avoid damaging storage devices that may still be in use
- To avoid damaging system and application files
- To avoid loss of data and information ( 3 mks) 36. A computer must go through the process of booting/ initialization before use (a) Briefly explain the term “computer booting”. Booting refers to the starting up of a computer. It is the entire process that makes the computer ready for use. (b) Explain what happens in the computer during the booting process When the power is switched on, internally, it first checks whether all the components are in good working condition, i.e. the RAM, CMOS (BIOS), hard disk & floppy disk drive controllers, and the keyboard. If no problem is found, it then loads the operating systems
(c) Give and explain two types of booting (i) Cold booting: It happens when a computer which was originally off is switched on by pressing the power
For free KCSE Notes, Exams, and Past Papers Visit https://Teacher.co.ke/
button on the systems unit The Computer starts by checking all its components to determine whether they are functioning properly
(ii) Warm Booting This happens when a computer that was originally on is forced to restart by pressing the restart button on the system unit by pressing a combination of keys on the keyboard ( CTRL
- ALT + DEL) (d) What type of memory is used to store the boot up program (the first program to be executed on switching on a computer? Read – only Memory (ROM) ( 1 mk)
37. (a) What is a computer keyboard An input device that lets the user enter commands into the computer for execution by typing
(b) List four types of keys found on a computer keyboard, giving an example of each ( 4 mks)
- Function/ command keys (F1- F12)
- Alphanumeric Keys (A-Z, 0-9)
- Numeric keypad (0-9)
- Cursor control keys (PgUp, PgDn, Home, end, Arrow keys)
- Special PC keys (Ctrl, Shift, Alt, Ins, Enter, Spacebar, Caps lock, Num lock, etc)
- Editing keys (Del, Backspace, and spacebar)
(c) Name the keyboard keys that will help you: (2 mks) (i) Type the upper character in a key - SHIFT Key (ii) Execute a selected command - ENTER Key For free KCSE Notes, Exams, and Past Papers Visit https://Teacher.co.ke/
