Transcript Document

The purpose of the course
give us a practical and theoretical
background into the use of
computers in a wide range of
domains
Help us become competent in
computer-related skills
How can information technology and
microcomputers enhance our life
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The purpose of this lesson
What is Information System?
What is IT?
What is a computer?
The main hardware units of the computer;
how they work, how they are
interconnected and how processing is
controlled in the computer.
From Page 6~Page 9
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Information Systems
People: make end users more productive
People who use microcomputers------end users
– Microcomputers: common tools in all areas
of life
– New forms of learning have developed
– New ways to communicate, to find people
with similar interests, and to buy goods are
available
Procedures: specify rules or guidelines for
computer operations
Software: provides step-by-step instructions for
computer hardware
Hardware: equipment that processes the data to
create information
Data: unprocessed facts
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Information Technology (IT)
deals with the use of electronic
computers and computerbased tool
to convert, store, protect,
process, transmit and retrieve
information, securely
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Computer Basics
What is a computer?
A computer is an electronic device,
operating under the control of
instructions stored in its own memory,
that can accept data, manipulate the data
according to specified rules, produce
results, and store the results for future
use.
Note: Computers can and do make mistakes.
- programming errors (common)
- hardware errors (less common)
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Hardware and Software
Hardware
 the electronic circuits and mechanical parts that physically make up the
computer
 include input devices, output devices, a system unit, storage devices, and
communications devices
Software
 the set of all the instruction combinations to control the
computer
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Monitor to
display
information
CD or DVD disk drive to
store and transport large
amounts of data
Speakers to play
sounds and music
System contains
electronic
components
Keyboard to input
instructions
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Mouse to
select items
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Components of a Computer
A computer may be divided into the following fundamental units
1. Central Processing Unit (CPU)
2. Memory Unit
3. Input/Output Unit (I/O)
INPUT/
OUTPUT
CPU
MEMORY
The three units are interconnected through various buses. A
bus is a set of wires (a physical path).
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Cartridge
containing
microprocessor
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System Unit
also known as a base unit
the main body of a computer
typically consisting of a metal or (rarely)
plastic enclosure containing
the chassis
CPU
memory
bus
ports
but does not include the keyboard or
monitor, or any peripheral devices
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Central Processing Unit
•The processor is the electronic component that interprets and
carries out the basic instructions that operate the computer
•CPU and processor mean the same.
•3 different parts
a) Arithmetic/Logic Unit (ALU)
 performs arithmetic and logic operations
b) Control Unit
 co-ordinates the machine's activities
 it interprets each instruction and then initiates the
appropriate action
c) Registers
 special memory cells in the CPU that are used as
temporary holding places.
 certain registers are assigned special tasks (eg. instruction
register, storage register, accumulator etc)
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Memory
 Memory
• stores data and program instructions
• each physical storage unit is assigned a unique address
• a location in main memory is accessed by its address
 Computer Memory Cell
 computers are electronic machines
 all data are stored by means of electrical charges
HIGH
0
LOW
1
 all numbers, characters, control signals, addresses etc are
coded into patterns of 0's and 1's
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Input/Output Unit (I/O)
• An input device is any hardware component that allows
you to enter data or instructions into a computer
•Six widely used input devices
– the keyboard
– Mouse
– Microphone
– Scanner
– digital camera
– PC video camera
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Output Device
• An output device is any hardware
component that conveys information to one
or more people
• Three commonly used output devices
– printer
– Monitor
– speakers
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Storage Devices
A storage device is capable of storing
data
The term usually refers to mass storage
devices
disks
tape drives
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Communications Devices
hardware component that enables a
computer to send (transmit) and
receive data, instructions, and
information to and from one or
more computers
A widely used communications
device is Modem
Other connection devices
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Software
also called a program
is the set of all the instruction
combinations to control the
computer
Two categories of software
System software
Application software
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System software
Consists of the programs that
manage and control the hardware
so that application software can
perform a task
An essential part of the computer
system
Two types of system software
Operating system
Utility programs
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Application Software
General-purpose
– Widely used in nearly every occupation
– Browsers, word processors, spreadsheets
– Database management system, presentation
graphics
Special-purpose
– Thousands of other programs
– Narrowly focused on specific occupations
– Multimedia, web authoring, graphics, virtual
reality
– Artificial intelligence programs
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Application Software
Common features of application software
– Window
– Menu
• Menu bar
• Pull down menu
• Options or commands
• Help menu
– Toolbars
• Standard toolbar
• Formatting toolbar
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Categories of Computers
• Supercomputers
• Mainframe computers
• Midrange computers
(Minicomputers)
• Personal Computers
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Supercomputers
A supercomputer is a computer that led
the world (or was close to doing so) in
terms of processing capacity,
particularly speed of calculation, at the
time of its introduction. It is the fastest,
most powerful and most expensive
computer
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Mainframe computers
A mainframe computer is a very large and
expensive computer capable of
supporting hundreds, or even
thousands, of users simultaneously.
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Midrange computers (Minicomputers)
A midrange computer refers to computers
that are more powerful and capable than
personal computers but less powerful
and capable than mainframe computers.
In the past, midrange computers were
known as minicomputers.
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Personal Computers
A personal computer is a small, singleuser
computer
based
on
a
microprocessor
It can perform all of its input, processing,
output, and storage activities by itself
Contains a processor, memory, one or
more input and output devices, and
storage devices
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Desktop Computers
A desktop computer is a computer made
for use on a desk in an office or home
and is distinguished from portable
computers such as laptops or PDAs
Desktop computers are also known as
microcomputers
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Notebook Computers
Notebook computer (also called notebook
or laptop) is a small mobile computer,
small enough that it can sit on your lap.
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Tablet PC
The tablet PC is a notebook- or slateshaped mobile computer
Its touchscreen or digitizing tablet
technology allows the user to operate
the computer with a stylus or digital pen,
or a fingertip, instead of a keyboard or
mouse
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Personal Digital Assistants (PDAs)
PDA is a handheld device that combines
computing, telephone/fax, Internet and
networking features
A typical PDA can function as a cellular
phone, fax sender, Web browser and
personal organizer
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Computer Memory Cell(1)
• all numbers, characters, control signals,
addresses etc are coded into patterns of 0's
and 1's
• A bit is a binary digit (0 or 1) and is the
computer's main unit of storage.
• A computer's memory cell holds a group of
bits which may represent
 numbers
 characters
 many other things
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Computer Memory Cell(2)
The contents of memory are usually groups of bits rather than
individual bits
Byte
 8 bits
Word
 the basic storage unit around which a computer is
designed
 a group of bytes
 some small computers have one byte words
other more powerful computers have
2
4
8
..
byte words
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Computer Memory Cell(3)
Kilobytes (KB) & Megabytes (MB), Gigabytes (GB)
KILOBYTE = 1024 B = 210 BYTES
MEGABYTE = 1024 KB = = 220 BYTES
GIGABYTE = = 1024 MB = 230 BYTES
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