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Introduction to Computers
Bizziland Training Center
To learn and be well versed with basic aspects of the Windows Interface and operation.
A computer is an electronic device whose purpose is to store and process data according to the
instructions given to it by people or in a variable program.
A computer system is made up of four main types of components. They include:
i) Input Devices (keyboard, mouse etc)
ii) Output Devices (monitor, speakers etc)
iii) Secondary Storage Devices (hard disk drive, CD/DVD drive etc)
iv) Processor and Primary Storage Devices (CPU, RAM)
Other components of a computer are:
 Power supply.
 Random-access memory (RAM)
 Sound card.
 Video card.
 Central processing unit (CPU)
 Motherboard.
 Network interface controller.
Computer hardware
This is the collection of physical parts of a computer system. It refers to the physical components of
a computer which includes the computer case, monitor, keyboard, and mouse. It also includes all the
parts inside the computer case, such as the hard disk drive, motherboard, video card, and many
others. Computer hardware is what you can physically touch, e.g. Keyboard, Mouse, and monitor.
System Software
Systems software includes the programs that are dedicated to managing the computer itself, such as
the operating system, file management utilities, and disk operating system (or DOS). The operating
system manages the computer hardware resources in addition to applications and data.
On the other hand, application software can be divided into two general classes: systems software
and applications software. Applications software (also called end-user programs) includes such
things as database programs, word processors, Web browsers and spreadsheets.
Peopleware refers to the role people play in technology and the development of hardware or software.
It can include various aspects of the process such as human interaction, programming, productivity,
teamwork, and other factors.
Functions of a Computer
1) Input 2) Storage 3) Processing 4) Output
 Input: Receiving or accepting information from outside sources. The most common way of
performing this function is through the information entered through the keyboard and the
click of mouse
 Processing: it is the main aim of a computer. The computer processes the data that is fed to
the computer by various means and the data already contained in internal memory to produce
the results that is the core of all computer application.
 Storage: Store information in the computer. The memory is stored in computer in in several
different ways depending on how the information is used. For simplicity we will classify in
two broad categories. First is the memory in the central processing unit of the computer, and
second is the auxiliary memory. The auxiliary memory includes devices such as fixed hard
drives. The information stored in computer can also be divided broadly used in two
categories. The user data and the instructions used for internal operation and processing in the
compute. These instructions are what we call computer programs or software.
 Output: The results of the processing are made available for use by any user or other devices.
The most common ways of producing such outputs are through computer monitor, speakers,
and printers. When a computer is connected to other devices, including through Internet, this
output is in the form of electrical pulses. The output data can also be recorded on to an
external recording medium such as a DVD, VCD, and flash disc.
Definition: The central processing unit (CPU) of a computer is a piece of hardware that carries out
the instructions of a computer program. It performs the basic arithmetical, logical, and input/output
operations of a computer system. ... The CPU is sometimes also referred to as the central processor
unit, or processor for short
- The CPU resides inside a box known as the system unit.
- The Disk Drive, located on the CPU is the location where Floppy disks can be inserted in
order to save or retrieve information on a computer.
The main role of the CPU is to sends signals to control the other parts of the computer, almost like
how a brain controls a body. The CPU is an electronic machine that works on a list of things to do,
called instructions.
The speed of a computer is measured in either MHz or GHz. The speed of the front side bus
determines how quickly the CPU can communicate with the graphics card, RAM and other
components. The bus speed is usually a ratio of the CPU's speed; the smaller the ratio, the more
efficient the processor.
GHz means 1 billion cycles per second and when you talk about 2.4 GHz processor, you usually
mean that this is the maximum frequency of the clock to each core. 1 processor can, and in the
PC/smartphone market usually does, have multiple cores that theoretically can have different clocks.
The main function of a computer monitor is to display video and graphical information generated by
the computers graphics adapter, allowing the user to interact with the computer. It is categorized as
an output device.
- Is only the part of the computer where information is projected onto the human eye
- Only way that the CPU can show the information to the person using it.
A monitor usually comprises the display device, circuitry, casing, and power supply. The display
device in modern monitors is typically a Thin Film Transistor Liquid Crystal Display (TFT-LCD)
or a flat panel LED display, while older monitors used a Cathode Ray Tubes (CRT).
The display provides instant feedback by showing you text and graphic images as you work or play.
Most desktop displays use liquid crystal display (LCD) or cathode ray tube (CRT) technology, while
nearly all portable computing devices such as laptops incorporate LCD technology.
CRT Monitor
TFT Monitor
Cathode Ray Tubes Monitor (CRT)
CRT is the technology used in traditional computer monitors and televisions. The image on a CRT
display is created by firing electrons from the back of the tube to phosphors located towards the front
of the display.
Thin Film Transistor
Short for thin film transistor, a type of LCD flat-panel display screen, in which each pixel is
controlled by from one to four transistors. The TFT technology provides the best resolution of all the
flat-panel techniques, but it is also the most expensive. TFT screens are sometimes called activematrix LCDs
In the computer world, a Serial Port is a connector by which a device that sends data one bit at a time
may be connected to a computer (in contrast to a parallel port). Over the years, computer data was
transferred through serial ports to devices such as modems, terminals and various peripherals.
Serial Ports
A USB port is a standard cable connection interface for personal computers and consumer
electronics devices. USB stands for Universal Serial Bus, an industry standard for short-distance
digital data communications. The advantage of a USB port is that it allows USB devices across the
globe to be connected to each other with and transfer digital data over USB cables. USB cables let
you attach accessories such as printers and cameras to your computer.
USB Adapter
A USB adapter is a type of protocol converter which is used for converting USB data signals to and
from other communications standards. Commonly, USB adaptors are used to convert USB data to
standard serial port data and vice versa.
USB Adopters/Connectors
A computer accessory refers to any device that is added to a computer that performs an additional
feature, but is not required. A good example of an accessory is the computer printer, which gives the
computer the ability to print, but the computer would still work if it didn't have the printer.
A peripheral device is generally defined as any auxiliary device such as a computer mouse or
keyboard that connects to and works with the computer in some way. Other examples of peripherals
are image scanners, tape drives, microphones, loudspeakers, webcams, and digital cameras.
- A mouse is a handheld and controlled pointing device that works by detecting twodimensional motion relative to a surface.
- It is an input device that enables a computer user to navigate one the screen based ones
choices by scrolling the scroll wheel or “clicking” on either the left or the right hand
Using the Mouse
The mouse is a hand-held pointing device used to enter information into your computer
The pointer, usually shown as a white small arrow on the screen, will follow the
movements you choose to do with the mouse. Move the mouse to the right, the pointer
will move to the right of the screen, etc.
Mouse Action
Clicking is the most common mouse action. Clicking means that using your
mouse you point at an object on the computer screen and then press and
quickly release the mouse button (normally the left button).
Double- Click
To double-click is to press the left button two times in rapid succession
without moving the mouse between clicks. This action is used to open icons or
Right Click
A Right Click or secondary click in to press and release the right button of the
mouse. This action often brings up context menus.
In order to drag an object on the screen, you must first point and click and hold
down the left button and move the mouse to the position where you want it.
Number of Keys on a Keyboard
There is no standard computer keyboard. Most keyboard manufacturers tend to imitate the keyboard
of Personal Computer. There are actually three different PC keyboard: the original PC keyboard with
84 keys, the AT keyboard also with 84 keys and the enhanced keyboard with 101 keys.
Keyboard Shortcuts
This refers to a key or combination of keys providing quick access to a particular function within a given computer
program. Keyboard shortcuts vary from one software application to another
Common Keyboard Shortcuts
CTRL+C (Copy)
CTRL+X (Cut)
CTRL+V (Paste)
CTRL+Z (Undo)
DELETE (Delete)
SHIFT+DELETE (Delete the selected item permanently without placing the item in the Recycle Bin)
CTRL while dragging an item (Copy the selected item)
CTRL+SHIFT while dragging an item (Create a shortcut to the selected item)
F2 key (Rename the selected item)
CTRL+RIGHT ARROW (Move the insertion point to the beginning of the next word)
CTRL+LEFT ARROW (Move the insertion point to the beginning of the previous word)
CTRL+DOWN ARROW (Move the insertion point to the beginning of the next paragraph)
CTRL+UP ARROW (Move the insertion point to the beginning of the previous paragraph)
CTRL+SHIFT with any of the arrow keys (Highlight a block of text)
SHIFT with any of the arrow keys (Select more than one item in a window or on the desktop, or select text)
CTRL+A (Select all)
F3 key (Search for a file or a folder)
ALT+ENTER (View the properties for the selected item)
ALT+F4 (Close the active item, or quit the active program)
ALT+ENTER (Display the properties of the selected object)
ALT+SPACEBAR (Open the shortcut menu for the active window)
CTRL+F4 (Close the active document in programs that enable you to have multiple documents open simultaneously)
ALT+TAB (Switch between the open items)
ALT+ESC (Cycle through items in the order that they had been opened)
F6 key (Cycle through the screen elements in a window or on the desktop)
F4 key (Display the Address bar list in My Computer or Windows Explorer)
SHIFT+F10 (Display the shortcut menu for the selected item)
ALT+SPACEBAR (Display the System menu for the active window)
CTRL+ESC (Display the Start menu)
ALT+Underlined letter in a menu name (Display the corresponding menu)
Underlined letter in a command name on an open menu (Perform the corresponding command)
F10 key (Activate the menu bar in the active program)
RIGHT ARROW (Open the next menu to the right, or open a submenu)
LEFT ARROW (Open the next menu to the left, or close a submenu)
F5 key (Update the active window)
BACKSPACE (View the folder one level up in My Computer or Windows Explorer)
ESC (Cancel the current task)
SHIFT when you insert a CD-ROM into the CD-ROM drive (Prevent the CD-ROM from automatically playing)
CTRL+SHIFT+ESC (Open Task Manager)
Using the Keyboard
The keyboard is an input device; some of its most important features are the following:
Num Lock
Ctrl (Control)
Caps Lock
What will do for you
The escape Key function is to get you out of problems. If you find
yourself in an unfamiliar menu or dialog box when using Windows,
pressing Esc backs you out.
By pressing this key, you add a line to your text and place the insertion
point in it. You can also use it to complete a command if you are
selecting from a menu or dialog box. This key can also be used to give
the OK to Windows so it will accept the information you have entered
in a dialog box or edit box.
By pressing this key, the numeric key pad (area with keys with numbers
on the right had side of the keyboard) is activated. Press it again if you
want to use the directional arrows and other cursor movement keys
located in the numeric keypad.
By pressing this arrow keys, the insertion point moves in the
appropriate direction.
Pressing the Ctrl key in combination with other keys you can take lots
of shortcuts. Example: pressing the Ctrl key + the S key saves the file
you are working on.
This key, like its predecessor on the old typewriter, changes lowercase
to uppercase letters. This key can be used in combination wit the Ctrl
key to create key combinations to perform specific functions. Also used
to type the symbols on the top row of your keyboard.
When you press this key, you can type in all uppercase letters without
having to hold the Shift key
When you are writing text pressing this key, it moves the insertion point
to the next field when filing a form or working with a database.
Basic parts of a computer are:
 Input Unit
 The Central Processing Unit
 Output Unit
Inside the CPU is the computer processor which is also known as a microprocessor or central
processing unit (CPU). The processor is a component in a computer system that functions as the
brains of a computer. It is mainly responsible for processing instructions of a computer program and
carrying out computer operations.
Images of the front and back
sides of a Computer
The computer does its primary work in a part of the machine we cannot see, a control center that
converts data input to information output. This control center, called the central processing unit
(CPU), is a highly complex, extensive set of electronic circuitry that executes stored program
A processor, or "microprocessor," is a small chip that resides in computers and other electronic
devices. Its basic job is to receive input and provide the appropriate output. ... The central processor
of a computer is also known as the CPU, or "central processing unit.
Speed of a Computer Machine
There are many factors which affect how fast your computer can process data and instructions: The
amount of RAM memory. The speed and generation of your CPU (the system clock) The size of the
Register on your CPU.
1. Improved productivity as multitasking, reliance on effective software applications, and use of
networked systems is encouraged.
2. Accuracy
3. It enhances communication and availability of information.
4. Efficiency: It increases cost efficiency at work and in other areas of life.
5. Storage capability:
6. It boosts storage capacity: With this networking technology, storage capacity and capability is
improved as one can do all of this without any hassle, while having all the space you need for
7. Versatility
8. It makes file sharing easier.
9. Proper organization: one can sort, organize, and search through information much faster
10. Creates many job opportunities
11. Automation and monitoring: computer systems can automate a wide variety of tasks. Any
imaginable can also be programmed and the computer made to respond in a certain way based
certain occurrences.
1. Lack thinking capacity – lacks own brain but instead work based on how it is programmed,
the software applications installed in it, and the instructions being given
2. Unlike human beings, computers do not learn from previous experience
3. Time wastage while doing unproductive activities
4. Physical inactivity: Computers have become more and easier to access thus making people to
become unbelievably lazy and physically inactive.
5. Poor blood circulation: most people who use computers sit in the same position for long
hours. Prolonged sitting is unhealthy as it leads to poor blood circulation thus fatigue in the
limbs, painful cramps and blood clots.
6. Encourages overeating and hence obesity.
7. Headache: Using computers for long hours can cause severe headache which a lot of people
complain about when they have to spend long hours working on the computer in office or at
8. Insomnia: sleeping patterns are interfered with as people have to stay hooked to computer and
internet has become a norm for a large number of youngsters these days.
9. Depression: spending too much time on computer can cause serious mental illness like
depression. Working on the computer often gives a lot of people a feeling of isolation like
they have lost contact with the real world.
10. Cyber crime: people can easy fall prey to cyber attackers. The risks include profile hacks,
online threatening and blackmailing, and privacy invasion.
11. Negative impact on education: students spend too much on social media instead of
studying…also makes plagiarism much easier.
Human beings have ears, nose, mouth, eyes
etc (input & output).
Have ability to remember
We recollect certain information as required.
We express ourselves by speech, writing etc
When we watch, hear, learn certain things and
The place where we store, analyze
Computers have input devices such as keyboard,
scanner, touch screen, mouse etc to get information.
Also store information (have memory)
The computer also retrieves information when times
Computer expresses through screen, Printouts etc
which We call as output.
With the help of software, computer also can
analyze Information and draw conclusions.
The computer brain is known as CPU conclude
information is known as the brain (Central
Unit) where it analyses information.