INTRODUCTION TO COMPUTER STUDIES
INTRODUCTION TO COMPUTER STUDIES
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
- Definition of a computer
- Parts of a computer
- Development of computers
- Classification of computers
- Physical Size
- Functionality
- Purpose
- Areas where computers are used
- Definition of a computer laboratory
- 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
- Hands-on skills
- Start-up
- restarting and shut-down (Booting)
- Keyboard layout
- Practical keyboard and mouse skill
INTRODUCTION TO COMPUTER STUDIES
Definition of a Computer
- It is an electronic device that transforms data to information.
Data: Raw facts. Information: Processed data.
A computer system is made up of two parts: Hardware and Software.
Hardware
- These are the physical parts of the computer printers, keyboard etc.
Software
- These are the programs (sets of instructions) that are used to run the computer e.g. Word processor, spreadsheet, database, presentation software etc.
Parts of hardware
- Hardware consist of three parts as follows.
Input Devices
- These are devices that are used to feed the computer with data for processing within. Examples include: Keyboard, mouse, scanners, digital cameras etc.
Output Devices
- These are devices that are used to give out information (processed data) from the computer to the user. Examples include: Monitors, Plotters, speakers etc. The output could take any of the following forms:
- Soft copy-this is output that is shown on the screen.
- Hardcopy-this is information printed on paper e.g. from a plotter, printer.
- Machine readable form- this is output that can only be read using the computer e.g. information stored on disks.
INTRODUCTION TO COMPUTER STUDIES
Central processing Unit
- The Central Processing Unit (CPU), motherboard, storage devices and other peripheral devices.
Peripheral Devices
- Devices connected directly or indirectly to the mother board.
Parts of the CPU.
- CPU is made up of three parts, namely:
Arithmetic Logic Unit
- The work of the ALU is to perform mathematical functions as well as do comparisons between units of data presented to it.
Control Unit
The work of the CU is to take data from an input device, to the processor/memory, then to an output device.
Memory
- The work of memory is to store data before, during and after processing.
Classification of Computers
- Size and Memory
- Purpose
- Functionality
Classification according to Size and Memory
- Supercomputer
- Mainframe
- Minicomputer
- Microcomputer
- Desktop
- Laptop
- 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
- General computers
This computer can do or handle a variety of tasks when loaded with appropriate programs.
- Special computers
They are designed to serve a specific purpose or to accomplish one particular task.
- 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.
- Storage:
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 etc..
Third Generation Computers (1964 – 1970)
They used Integrated Circuit (IC)
Advantages
Smaller in size
More reliable than the previous ones
Emitted lesser heat than the previous ones
Less maintenance cost
Less power consumption than the first and the second generation
Disadvantages
Highly sophisticated for the manufacture of Integrated Circuit
Costly
Examples
IBM360, BurroughsB5600
Fourth Generation Computers (1970-1989)
The are characterized by the use of Large Scale Integrated Circuit (LSIC)
Advantages
Smaller in size
More reliable than previous generation computers
Generated a lot of heat
Faster than previous generation computers
Less prone to hardware failure
Portable
Disadvantages
Highly sophisticated technology in manufacturing of Large Scale Integrated chip
Examples
IBM3033, Buroughs67700
Fifth Generation Computers (From 1989)
Expected to do parallel processing
Based on logical inference operations
Expected to make use of artificial intelligence
Features of a Computer
Automation: Computers work with minimum human intervention once supplied with data and instructions.
Accuracy: Computers are ever accurate but entirely depend on the data entered.
Speed: Performs tasks in very short period.
Storage: Computers can store large volumes of data and information.
Versatile: Ability of doing different tasks as per instructions.
Diligence: Work for a long period of time without getting bored
Disadvantages of Computers
Computers are very expensive
Cuts down on employment opportunities
Needs expertise which is expensive to hire and maintain
They create eye problems
Loss of information if not well managed
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 centers.
- 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
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.
Keyboard Layout
- Alphanumeric Keys
Comprises of numbers and all alphabets, symbols like @,!,$,%,^,&,*,(,),?,>,< etc.. Other keys include Caps lock, Enter key, Tab, Spacebar, Back space.
- a) Caps Lock: When on letters typed appear in uppercase and when of letters appear in lowercase.
- b) Enter keys: When pressed it forces the cursor to move to the beginning of the next line.
- c) Tab keys: Used to move the cursor at set intervals.
- d) Back space: Deletes characters to the left from the cursor position.
- Function keys
They are always located along the top of the keyboard. They are labeled F1, F2 to F12.
- Cursor Movement and Editing Keys
Cursor Movement Keys
- a) Arrow Keys: Used to move the cursor up, down, left and right.
- b) Page up and page down keys: Moves the cursor one page up or down.
- c) Home and End keys: Pressing Home key moves the cursor to the beginning of the current
line. End key moves the cursor to the end of the current line.
Editing Keys
- a) Insert key: It helps the user to insert or replace a character at the cursor position.
- b) Delete (Del) key: This key deletes characters at the cursor position from left to right.
- Special PC Operation Keys
They are rarely used singly but in combination with other keys to give special instructions to the
computer. They include SHIFT, CTRL, ALT and ESC.
- Numeric Keypad
Consist of a set of numbers 0 to 9 and the arithmetic signs +,-, *, / and are located on the right side of the keyboard.
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 referred 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.
- 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
– 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 device
(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
- 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
– Consumed a lot of power
– Produced a lot of heat
– The computers constantly broke down due to the excessive heat generated; hence were short- lived, and were not very reliable
– Their internal memory capacity/ size was low
– Processing speed was very slow
– Very costly
– Used magnetic drum memory
- Briefly explain the classification of computer according to historical development (generations)
First generation computers
– Used vacuum tubes in their memory
– Large in physical size
– consumed a lot of power
– Produced a lot of heat
– The computers constantly broke down due to the excessive heat generated; hence were short- lived and were not very reliable
– Their internal memory capacity/ size was low
– Slow in processing data
– Very costly
– Used magnetic drum memories
– Cards were sued to enter data into the computers
Second generation computers
– Used transistors in their memory
– They consumed less power & produced less heat than the first generation computers
– They were relatively faster than the 1st generation computers
– Used magnetic core memories
– Were less costly than first generation computers
– RAM memory capacity was 32 KB
Third Generation computers
– Used integrated circuits in their memory
– They were faster than second generation computers
– RAM memory capacity was 2 GB
– Slightly smaller in size than 1st & 2nd generation computers
– They used a wide range of peripheral devices
– Could support remote communication facilities/ more than one user at the same time
– Magnetic disks were introduced for storage purposes
Fourth generation computers
– Used large scale integrated (LSI) circuits & very large scale integrated (VLSl) circuits in their memory
– 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
- State four factors used to classify computers
– Physical size & processing power
– Power
– Functionality (mode/ method of operation)
– Type of processor (CPU)
- 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
- (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
- Which category of computers would you place an N- series Nokia phone
– Microcomputer/ palmtop
- 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)
– It has a keypad
– It has a memory for storage
– It is programmable
- (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
- State a specific example where each of the following types of computers can be used
(a) Supercomputer
– Weather forecasting
– 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
- – Communication centers as terminals
- – Small business enterprises e.g. shops, small offices and homes
- (a) Define a microcomputer ( 1 mk)
– A computer who’s CPU (processor) has been implemented with a microprocessor
(b) Differentiate between a microcomputer and a personal computer ( 2 mks)
– A microcomputer is larger in physical size than a PC
– A microcomputer is more powerful than a PC
– A PC was designed to be used by one person only
(c) List three factors to be considered when purchasing a microcomputer (3 mks)
– Type of processor
– Processing speed
– Amount of main memory (RAM)
– Storage capacity of the hard disk
– Cost of the computer
– Speed of output devices
– Number of users who can access the computers at the same time
- Explain four reasons which make microcomputers suitable for personal computing work
– Reduced cost, i.e. are cheaper than the minicomputers & mainframe computers
– Have high processing speed
– Are small in size (occupy less office space)
– Are more energy efficient (i.e. consume less power)
– Are more reliable in doing various functions than the early mainframe computers
– Are versatile (i.e. can be used for many different tasks)
- (a) Identify and explain five areas where computers are used to process data ( 10 mks)
Supermarkets
– For stock control i.e. records of what is in store, what has been sold, and what is out of stock
– For calculating customer’s change
– For production of receipts
– It can be used as a barcode reader
Banks
– Manage financial transactions through the use of special cash dispensing machines called ATMs used for cash deposit & withdrawal services
– Processing of cheques
– For preparation of payrolls
– Better record keeping & processing of documents
– Provide electronic money transfer facilities
Homes
– 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
- 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
- (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
– The maximum number of users that the laboratory can accommodate
- 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
- 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
- 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
- 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
- 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
- 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
- (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
(b) List down four functions of the uninterruptible Power Supply (UPS) (4 mks)
– It prevents sudden power surges that might destroy the computer
– It supplies power to the Computer during blackouts and brownouts
– It provides stable (clean) power supply
– Alerts the user of power loss (by beeping)
– Allows the user to save his/ her work, and switch off the system using the correct procedure
- Mention two things that are likely to cause strain- in the computer room
– Poor lighting of the room
– Bright monitors
– Flickering monitors
– Very bright wall paints reflect too much light
- Identify three proper sitting postures while using the computer
– Adopt relaxed and straight back position to avoid bending forward or learning far backwards
– The feet should be firmly placed flat on the floor
– The seat must be high enough allowing the eyes to be the same level with the top of the
Screen
– The seat must have a straight backrest that allows someone to sit upright. This prevents muscle pains & backaches caused by poor sitting posture
– The height of the chair or working surface must be high enough such that your forearms are parallel with the floor and your wrists are straight.
– The seat must be high enough relative to the table to enable the user use the hands on the peripheral devices comfortably.
- State two methods of minimizing dust in a computer laboratory
– Fit the computer room with special curtains to reduce entry of dust particles
– Cover the floor with carpets in order to absorb dust
– Regular cleaning of the laboratory
– Cover the computer devices with dust covers when cleaning the room
- Name two main causes of fire in the computer laboratory and give the precautions that should be taken to guard against them
– Inflammable chemical such as those used to clean the computer equipment
Keep the chemicals away in store after use
– Open wires/ cables
– Ensure that all electrical wires are properly insulated
– Ensure that the computer room has a gaseous fire extinguisher containing carbon dioxide in case of any accidents
– Smocking
- What is the purpose of labeling a diskette?
– To prevent confusing the data in the different diskettes
– To prevent mixing diskettes that are used everyday with those used for long- term storage of important data.
- 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
- 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
- (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)
- 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 button on the systems unit
The Computer starts by checking all its components to determine whether they are functioning properl
(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)
- (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