Basic Structure and Functions of Computers
Session 2: Basic Structure and Functions of Computers
Total Session Time: 120 minutes
Prerequisites
Session 1
Learning Tasks
By the end of this session, students are expected to be able to:
Explain structure of a computer
Describe Different Types of Computer Generations
Describe Major Parts of a Computer and its Function
Explain Back-up Systems and their Importance
Identify Different Devices and Peripherals of a Computer
Resources Needed
Flip charts, marker pens, and masking tape
Black/white board and chalk/whiteboard markers
Computer
LCD
SESSION OVERVIEW
Step
Time
Activity/Method
Content
1
05 minutes
Presentation
Presentation of Session Title and Learning Tasks
2
20 minutes
Presentation
Buzzing
Structure of Computer
3
20minutes
Presentation
Types of Computer Generation
4
30 minutes
Presentation Brainstorming
Major Parts of Computer and its Function
5
25 minutes
Presentation Buzzing
Back-up Systems and their Importance
6
5 minutes
Presentation
Devices and Peripherals of a Computer
7
05 minutes
Presentation
Key Points
8
05 minutes
Presentation
Evaluation
9
05 minutes
Presentation
Assignment
SESSION CONTENT
Step 1: Presentation of Session Title and Learning Tasks (5 minutes)
READ or ASK students to read the learning objectives and clarify.
ASK students if they have any questions before continuing
Step 2: Structure of Computer (20 minutes)
Activity: Buzzing (5 minutes)
ASK students to pair up and buzz on the following question for 5 minutes
What are the structures of a computer?
ALLOW few pairs to respond and let other pairs to add on points not mentioned
WRITE their response on the flip chart/board
CLARIFY and SUMMARIZE by using the content below
Computer is created to simplify jobs of different type according to the user needs.
User of the computer is the one who commands the computer and tells it what to do
User tells computer what to do by entering data using keyboard then result will be displayed on the screen
The process of entering data into computer is called data entry.
This process of entering data to a computer is done by user, in which data will be processed in order to get information
User will use input devices such as keyboard and mouse to enter data in the system then the data will be processed to produce information
The result which is output will be shown in a monitor or through printed document
Below are the procedures and diagram used by computer to execute data
First
Data is entered through input devices e.g. keyboard.
Second
Control Unit (CU) after receiving instruction from the main memory to send signal and commands, CU send signal and commands to various parts of the computer system to prepare and accept the data
After the data is processed it is sent back to main memory which stores it temporarily before the next command is executed
The data is then sent to secondary storage devices after secondary storage device had received command from the Control Unit
For the information to be put into a hard copy i.e. paper, the information moves from the secondary storage device to the main memory which waits for signals and commands from Control Unit
After receiving signal from the Control Unit that the output devices are ready to receive data, the main memory releases the data to the output devices like printers
Third
Output devices translate the processed information from the computer into a form that humans can understand
The most common output devices are monitors or video display screen and printers.
Lastly
Secondary storage devices hold data and program even after electrical power to the computer has been turned off
The most important kinds of secondary media are floppy, hard and optical disks
Figure 9: Structure of Computer
Source: Slideshare.net
Step 3: Types of Computer Generations (20 minutes)
Computer generation is categorized into five generation
First Generation
Second Generation
Third Generation
Fourth Generation
Fifth Generation
First Generation 1946-1959.
The computers of first generation used vacuum tubes as the basic components for memory and circuitry for CPU (Central Processing Unit)
These tubes, like electric bulbs, produced a lot of heat and were prone to frequent fusing of the installations, therefore, were very expensive and could be afforded only by very large organizations
In this generation mainly batch processing operating system were used
Punched cards, paper tape, and magnetic tape were used as input and output devices
The computers in this generation used machine code as programming language
Figure 4: 1st Generation Computer
Source: tutorialspoint.com
The Main Features of First Generation
Vacuum tube technology
Unreliable
Supported machine language only
Very costly
Generated lot of heat
Slow input and output devices
Huge size
Need of A.C.
Non-portable
Consumed lot of electricity
Second Generation 1959-1965.
In this generation transistors were used that were cheaper, consumed less power, more compact in size, more reliable and faster than the first generation machines made of vacuum tubes
In this generation, magnetic cores were used as primary memory and magnetic tape and magnetic disks as secondary storage devices
In this generation assembly language and high-level programming languages like FORTRAN, COBOL was used
The computers used batch processing and multiprogramming operating system.
Figure 5: 2nd Generation Computer
Source: tutorialspoint.com
The Main Features of Second Generation
Use of transistors
Reliable in comparison to first generation computers
Smaller size as compared to first generation computers
Generated less heat as compared to first generation computers
Consumed less electricity as compared to first generation computers
Faster than first generation computers
Still very costly
A.C. needed
Supported machine and assembly languages
Third Generation 1965-1971.
The computers of third generation used integrated circuits (IC's) in place of transistors
A single IC has many transistors, resistors and capacitors along with the associated circuitry
The IC was invented by Jack Kilby. This development made computers smaller in size, reliable and efficient
In this generation remote processing, time-sharing, multi-programming operating system were used
Figure 5: 3rd Generation Computer
Source: tutorialspoint.com
The Main Features of Third Generation
IC used
More reliable in comparison to previous two generations
Smaller size
Generated less heat
Faster
Lesser maintenance
Still costly
A.C needed
Consumed lesser electricity
Supported high-level language
Fourth Generation 1971-1980
The computers of fourth generation used Very Large Scale Integrated (VLSI) circuits.
VLSI circuits having about 5000 transistors and other circuit elements and their associated circuits on a single chip made it possible to have microcomputers of fourth generation
Fourth generation computers became more powerful, compact, reliable, and affordable.
As a result, it gave rise to personal computer (PC) revolution
In this generation time sharing, real time, networks, distributed operating system were used
All the high-level languages like C, C++, DBASE etc., were used in this generation
Figure 6: 4th Generation Computer
Source: tutorialspoint.com
The Main Features of Fourth Generation
VLSI technology used
Very cheap
Portable and reliable
Use of PC's
Very small size
Pipeline processing
No A.C. needed
Concept of internet was introduced
Great developments in the fields of networks
Computers became easily available
The Period of Fifth Generation 1980-Till Date
In the fifth generation, the VLSI technology became ULSI (Ultra Large Scale Integration) technology, resulting in the production of microprocessor chips having ten million electronic components
This generation is based on parallel processing hardware and AI (Artificial Intelligence) software
AI is an emerging branch in computer science, which interprets means and method of making computers think like human beings.
All the high-level languages like C and C++, Java, .Net are used in this generation.
AI includes:
Robotics
Neural Networks
Game Playing
Development of expert systems to make decisions in real life situations.
Natural language understanding and generation
Figure 7: 5th Generation Computer
Source: tutorialspoint.com
The Main Features of Fifth Generation
ULSI technology
Development of true artificial intelligence
Development of Natural language processing
Advancement in Parallel Processing
Advancement in Superconductor technology
More user friendly interfaces with multimedia features
Availability of very powerful and compact computers at cheaper rates
Some Computer Types of This Generation
Desktop
Laptop
Notebook
Ultra Book
Chrome Book
Step 4: Major Parts of a Computer and its Function (30 minutes)
Activity: Brainstorming (5 minutes)
Ask students to brainstorm on the following question:
What are major parts of a computer?
ALLOW few students to respond
WRITE their responses on the flip chart/ board
CLARIFY and SUMMARISE by using the content below
Computer is made up by hardware and software
Hardware
Hardware is the equipment that processes the data to create information and is controlled by software. It includes
Keyboard
Mouse
Monitor(Screen)
Central Processing Unit CPU)
System unit
Random Access Memory(RAM)
Figure 8: Diagram of computer parts
Source: myimagecollection.net
Software
Software is another name of a program or programs. The purpose of software is to convert data (unprocessed facts) into information (processed facts)
Software programs consist of the step-by-step instructions that tell the computer how to do its work or set of instruction which tell computer what to do
In order computer physical part (hardware) to work properly there must be software. Software is set of instruction which tell computer what to do
There are two types of software, these are system software and application software
System Software
System software consists of programs that control the operations of a computer and its devices
System software serves as the interface between a user, the application software, and the computer’s hardware. One type of system software is the operating system
Before application software can be run, the operating system, which contains instructions that coordinate the activities among computer hardware devices, must be loaded from the hard disk into the computer’s memory
Application Software
Application software consists of programs designed to perform specific tasks for users.
Application software can be used as a productivity/business tool; to assist with graphics and multimedia projects; to support home, personal, and educational activities and to facilitate communications.
Specific application software products is called program and are available from software vendors.
Functions of major parts of a computer
Keyboard
Keyboard is an input device, partially modeled after the typewriter keyboard, which uses an arrangement of buttons or keys, to act as mechanical levers or electronic switches
After punch cards and paper tape, interaction via teletype-style keyboards became the main input device for computers
Mouse
Computer’s mouse controls a graphical mouse pointer or mouse cursor on the screen.
When you move the mouse around by rolling it on your desk, the pointer on the screen moves in a similar manner
Roll the mouse left, and the pointer moves left; roll it in circles, and the pointer mimics that action
Basic mouse operations:
Point: When you’re told to “point the mouse,” you move the mouse on the desktop, which moves the mouse pointer on the screen to point at something interesting (or not).
Click: A click is a press of the mouse button — one press and release of the main button, the one on the left. This action makes a clicking sound, which is where this maneuver gets its name.
Clicking is often done to select something or to identify a specific location on the screen.
Right-click: This action is the same as a click, although the right mouse button is used to get more commands.
Double-click: This one works just like the single click, although you click twice in the same spot — usually, rather rapidly.
This is most commonly done in Windows to open something, such as an icon
Both clicks must be on (or near) the same spot for double-click to work
Drag: The drag operation is done to graphically pick up something on the screen and move it.
To do that, you point the mouse at the thing you want to drag, press and hold the mouse’s button (which “picks up” the object), and then move the mouse to another location
When you move the mouse (and keep the button down), the object moves
To release, or drop, the object, release the mouse button
Speakers
This is output device which use to convert electrical energy into sound
It consist essentially a thin flexible sheet called diaphragm that is made to vibrate by electrical signal from amplifier
Central processing Unit (CPU)
CPU is also called a processor, significantly impacts overall computing power and manages most of a computer’s operations
This is the component that actually executes instructions
The CPU contains
Control unit
Arithmetic / logic unit (ALU)
Control unit directs and coordinates most of the operations in the computer
For every instruction, the control unit repeats a set of four basic operations called the machine cycle:
Fetching the instruction or data item from memory
Decoding the instruction into commands the computer understands
Executing the commands, and, if necessary
Storing, or writing the result to memory
Arithmetic/logic unit (ALU) performs the execution part of the machine cycle. Specifically, the ALU carries out three operations:
Arithmetic operations – performing calculations, which include addition, subtraction, multiplication, and division
Comparison operations – comparing data items to determine if the first item is greater than, equal to, or less than the other item
Logical operations – working with conditions and logical operators such as AND, OR, and not
Monitor
This is sometimes called screen or visual display unit.
This is an output device for electronic visual display on computers.
It allow user to see the data which entering into a computer and results after processing the data
Hard disk drive
Is a non- is a non-volatile storage device for digital data.
This means permanent storage
Hard disk is used to store all programs used by computer permanently and it is within the system
Random access memory (RAM)
RAM is a form of computer data storage
It enables computer to store at least temporarily data and programs.
RAM is often associated with volatile types of memory
This means that its contents are lost when the computer is turned off
In general, memory (RAM) is fast and short-term
Read-Only Memory (ROM)
Read Only Memory is a storage medium that is used with computers and other electronic devices
As the name indicates, data stored in ROM may only be read; it is either modified with extreme difficulty or not at all
ROM is mostly used for firmware updates
A simple example of ROM is the cartridge used with video game consoles
Printer
This is an output device which allows user to view results in paper page
Uninterrupted Power Supply (UPS)
Is an electrical apparatus that provides emergency power to load when the input power source fail
Power supply
It is the component that supplies power to the other components in a computer system
Step 5: Back-up Systems and their Importance (25 Minutes)
Activity: Buzzing (5 minutes)
ASK students to pair up and buzz on the following question for 2 minutes
What is backup system?
ALLOW few pairs to respond and let other pairs to add on points not mentioned
WRITE their response on the flip chart/board
CLARIFY and SUMMARIZE by using the content below
Backup refers to the copying and archiving of computer data so it may be used to restore the original after a data loss event. The verb form is to back up in two words, whereas the noun is backup
Data Backup is the result of copying or archiving files and folders for the purpose of being able to restore them in case of data loss
Data loss can be caused by many things ranging from computer viruses to hardware failures to file corruption to fire, flood, or theft
As part of a data backup plan, you should consider the following:
What data (files and folders) to backup
What compression method to use
How often to run your backups
What type of backups to run
What kind of media on which to store the backups
Where to store the backup data for safekeeping
What Data Should I Back up?
In general, you should back up any work or data that can't be replaced easily.
Some examples are word processing documents, spreadsheets, databases (for financial data), customer data, and personal files such as pictures, music files and emails
What Compression Method Should I Use?
You can use Best method compression with any or your backups.
This will insure that your Zip files will be as small as possible.
If you have a preferred compression method or if you would like the Zip files to be created more quickly, you have the option to choose a different method.
How Often Should I Run my Backups?
The frequency to run your backups depends on how often the data changes.
Business data that changes frequently may need daily or hourly backups
Data that changes every few days might use a weekly or even monthly backup
For some data, you might run your backup whenever you make a change
What Kind of Media Should I Use and Where Should I Store my Backups?
You can store your backup files on any file storage media you have.
The most common examples for a home user would be an additional local hard drive, an external hard drive, optical discs (CDs, DVDs, or Blu-ray discs), or flash drives.
A best practice for storing backups is to keep a copy of the backup files on-site (in your home or office) for easy access and a copy off-site in case of fire, flood, or other damage to your location which could damage or destroy the on-site backup copy.
Types of Backup Equipment
Magnetic Tape
Magnetic tape has long been the most commonly used medium for bulk data storage, backup, archiving, and interchange.
Tape has typically had an order of magnitude better capacity/price ratio when compared to hard disk, but recently the ratios for tape and hard disk have become a lot closer.
Some new tape drives are even faster than modern hard disks.
Hard Disk
The capacity/price ratio of hard disk has been rapidly improving for many years.
This is making it more competitive with magnetic tape as a bulk storage medium.
The main advantages of hard disk storage are low access times, availability, capacity and ease of use.
Optical Storage
Recordable CDs, DVDs, and Blu-ray Discs are commonly used with personal computers and generally have low media unit costs.
However, the capacities and speeds of these and other optical discs are typically an order of magnitude lower than hard disk or tape.
Solid State Storage
Also known as flash memories, thumb drives, USB flash drives, Compact Flash, Smart Media, Memory Stick, Secure Digital cards.
These devices are relatively expensive for their low capacity in comparison to hard disk drives, but are very convenient for backing up relatively low data volumes.
Remote Backup Service
As broadband Internet access becomes more widespread, remote backup services are scenarios such as fires, floods, or earthquakes which would destroy any backups in the immediate vicinity along with everything else.
There are, however, a number of drawbacks to remote backup services. First, Internet connections are usually slower than local data storage devices.
Secondly, users must trust a third party service provider to maintain the privacy and integrity of their data, although confidentiality can be assured by encrypting the data before transmission to the backup service with an encryption key known only to the user
Floppy Disk
During the 1980s and early 1990s, many personal/home computer users associated backing up mostly with copying to floppy disks. However, the data capacity of floppy disks failed to catch up with growing demands, rendering them effectively obsolete.
gaining in popularity.
Backing up via the Internet to a remote location can protect against some worst-case
Step 6: Devices and Peripherals of a Computer (5 Minutes)
LCDs
Printer
Un-interrupted Power Supply (UPS)
HPLC Machines
X-Rays Machines
Ultra sound
Public Addressing (PA) System
Step 7: Key Points (5 minutes)
Computer is created to simplify jobs of different type according to the user needs
The computers of first generation used vacuum tubes as the basic components for memory and circuitry for CPU (Central Processing Unit)
Data backup is the result of copying or archiving files and folders for the purpose of being able to restore them in case of data loss.
Devices and peripherals of a computer are UPS, printer, LCDs, speakers, x-rays, HPLC and Ultra-sound machines
Step 8: Evaluation (5 minutes)
What is the structure of computer?
How many computer generations are there?
What are major parts of a computer?
What are the different types of backup equipment?
Step 9: Assignment (5 Minutes)
Activity: Take home Assignment (5 minutes)
DIVIDE student in groups or individual
ASK the student to work on the following assignment
Using your own words how can you differentiate between RAM and ROM
ALLOCATE time for student to do the assignment and submit
REFER student to recommended references
Reference
Bott, E. & Siechert, C. (2001). Microsoft Windows XP Inside Out. Microsoft Press
Ventage Press.
CPU. Retrieved from www.webopedia.com/TERM/C/CPU.html
Herniter, M.E. (2000). Personal computer fundamentals for students, hardware windows 2000 Application (2nd ed). Prentice Hall.
Joos, I. Whitman, N. Smith, M. Nelson, R. et al. (2006). Introduction to computers for
healthcare professionals (4th ed). Barb Mews: London.
Morris, M. & Charles, M. (2003). Logol Computer Designer Fundamentals. Prentice Hall.
University: Boston Burr Ridge.
Sagman, S. (1999), Microsoft Office 2000 for Windows: Visual Quick Start Guide. Peachpit Press
The Basics of the Word Window. Retrieved from www. tutorialspoint.com
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