Transcript Introduction to Computer Organization and Architecture

Introduction to Computer
Organization and Architecture
What is a Computer?
A computer is an electronic
device that stores, accepts data,
retrieves data, processes data
and gives output according to a
set of instructions.
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Elements of a computer
 Hardware

Physical components
 Software

Computer instructions
 User

Human operator
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Main Hardware Components
Input
CPU
Device
Output
Device
Backing
Store
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Hardware
• This is the equipment that make up a
computer system (physical
components).
• Many of these parts are contained
within the computer’s case.
• Other parts are connected to the
computer (peripheral devices).
These allow data to be entered
(input) and retrieved (output) and
stored
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Computer Hardware components
• Input devices (mouse and keyboard) let
the user enter data
• Processing devices (processor)
• Output devices (monitor, speakers and
printer) display data
• Storage devices (memory sticks and
disks) hold data
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Central Processing Unit
• The part of the computer performs the bulk of data
processing operations is called the central
processing unit
• “Brain” as well as “heart” of computer system
• The chip or chips at the heart of a computer that
enable it to process data.
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CPU Components
• The CPU is made up of four major parts:
–
–
–
–
Register set
ALU
Control units
Main memory
• Memory: An area within a computer system that holds data
waiting to be processed.
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Components of the CPU
• Control unit
– Control unit: supervises the transfer of information
among the registers and instructs the ALU as to which
operation to perform by generating control signals.
• Arithmetic logic unit (ALU)
– Performs computation and comparison operations
• Set of registers
– Storage locations that hold inputs and outputs for the ALU
– Stores intermediate data during the execution of
instructions;
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CPU Registers
• Primary functions
– Hold data for currently executing program that is
needed quickly or frequently (general-purpose
registers)
– Store information about currently executing
program and about status of CPU (special-purpose
registers)
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Input
Devices
•
Input is any data entered into the computer’s memory.
•
input devices : the devices that allow data and instructions to
enter a computer (such as a keyboard, mouse, scanner)
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Input
Devices
• Types of input include:
– Data – Unorganized information (words,
numbers, images, or sounds) that the computer
converts to meaningful information
– Software – Programs transferred from storage
devices to the computer’s memory
– Commands – Instructions that tell the computer
what to do
– Responses – Prompts requiring user feedback
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Definitions
• Input device is any device that is used to
transfer data into a computer so that it may
be processed or stored permanently.
• Each type of input device has an INTERFACE i.e
a means of communication between the
human user and the electronic computer
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Modern data capture Methods
• Data may be keyed in from source documents
by keyboard operators
 Computer Keyboard
 Numeric keypad
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Modern data capture Methods c.t.d.
• The source documents may be read directly by a
document reader. Document readers capture
information in the form of pictures or text already
printed on paper.
 Image Scanners
 Optical Character reader (OCR)
 Optical Mark reader (OMR)
 Magnetic ink character reader (MICR)
 Bar code readers
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Modern data capture Methods ctd
• Data may be captured directly without the
need for any source document
 Magnetic strip on a plastic card,
 Smart card
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Modern data capture Methods ctd
• Graphic input devices may be used to translate
drawings or photographs into digital form that
can be processed by a computer
 Mouse
 Track ball
 Touch screen
 Digitizing tablet
 Light pen
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Sound Input
• A microphone can be attached to a sound
card to provide audio input and also to issue
commands and crate files
• Speech recognition is a type of input in which
the computer recognizes words spoken into a
microphone.
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Output Devices
• Output devices are peripheral devices that
enable us to view or hear the computer’s
processed data. E.g. a display screen or
printer)
• Output: The product of the transformation
of inputs by a process.
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Output Devices
• Types of output
– Visual output – Text, graphics, and video
– Audio output – Sounds, music, and synthesized
speech
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Monitors
• A monitor is a peripheral device which
displays computer output on a screen.
• Screen output is referred to as soft copy.
• Types of monitors:
– Cathode-ray tube (CRT)
– Liquid Crystal Display (LCD or flat-panel)
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Printers
• A printer is a peripheral device that
produces a physical copy or hard copy of the
computer’s output.
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Types of Printers
Laser
•
•
•
•
Laser printer works like a copier
Quality determined by dots per inch (dpi) produced
Color printers available
Expensive initial costs but cheaper to operate per page
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Types of Printers ctd
Inkjet
• Inkjet printer, also called a bubble-jet, makes characters by
inserting dots of ink onto paper
• Letter-quality printouts
• Cost of printer is inexpensive but ink is costly
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Plotter
• A plotter is a printer that uses a pen that moves
over a large revolving sheet of paper.
• It is used in engineering, drafting, map making,
and seismology.
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Audio Output: Sound Cards and
Speakers
• Audio output is the ability of the computer to
output sound.
• Two components are needed:
– Sound card – Plays contents of digitized recordings
– Speakers – Attach to sound card
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Computer Sorage
• Storage device:
– The place where a computer puts data.
– The area within a computer system where data
can be left on a longer term basis while it is not
needed for processing.
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Why Is Storage Necessary?
• Storage devices:
–Retain data when the computer is turned off
–Are cheaper than memory
–Play an important role during startup
–Are needed for output
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Storage Technologies: Magnetic and
Optical
Optical Storage –
CD/DVD drive
Magnetic Storage
• Magnetic – Storage devices use disks or tapes
that are coated with magnetically sensitive
material
• Optical – Storage devices that use laser beams to
read patterns etched into plastic disks
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CD-ROM Discs and Drives
• CD-ROM stands for Compact DiscRead Only Memory.
• CD-ROM drives can not write data
to discs.
• They are capable of storing 650 MB
of data.
• They are used for storing operating
systems, large application programs,
and multimedia programs.
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CD-R and CD-RW Discs and Recorders
CD-R
• Discs can be read and written to
• Discs can only be written to “once”
• CD-R drives are capable of reading and writing data
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CD-R and CD-RW Discs and Recorders
CD-RW
• Discs can be read and written to
• Discs are erasable
• Discs can be written to many times
• CD-RW drives are capable of reading, writing, and
erasing data
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DVD-ROM Discs and Drives
• DVD stands for Digital Video Disc.
• DVD technology is similar to CD-ROM
technology.
• DVDs are capable of storing up to 17GB
of data.
• The data transfer rate of DVD drives is
comparable to that of hard disk drives.
• DVD-R and DVD-RW drives have the
ability to read/write data.
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Solid State Storage Devices
• Solid state storage devices use nonvolatile
memory chips to retain data.
• They do not have moving parts.
• They are small, lightweight, reliable, and
portable.
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Solid State Storage Devices
Smart
Card
Flash
Memory
PC
Card
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Solid State Storage Devices
Memory
Stick
Compact
Flash
Memory
Micro
Drive
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