COMPUTER ARCHITECTURE &
ORGANIZATION
Introduction
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CONTENTS

Introduction to Basic Computer

Computer Architecture and Organization
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INTRODUCTION TO BASIC COMPUTER
What is Computer?
 A device that accepts input, processes data, stores
data, and produces output, all according to a series of
stored instructions.
 An electronic device that has the ability to store,
retrieve, and process data and can be programmed
with instructions that it remembers.
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INTRODUCTION TO BASIC COMPUTER
What is Computer?
 Hardware
 The physical parts that make up a computer
 Includes CPU, Memory, I/O device…
 Software
 Programs that tell a computer what to do
 Includes Operating system and other application software
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BIG PICTURE

Since 1946 all computers have had 5 components
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COMPUTER FUNCTIONAL UNITS
 INPUT
UNIT
 Converts
the external world data to a binary
format, which CUP can understand
 Mouse,
Joystick , Keyboard etc
 OUTPUT
UNIT
 Converts
the binary format data to a format
that a common man can understand
 Monitor,
Printer, LCD, LED etc
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COMPUTER FUNCTIONAL UNITS..
 CPU
(Central Processing Unit)
 The
“brain” of the machine
 carrying
 ALU,
out computational task
Control unit, Registers

Arithmetic and logical operations

CU Provides control signals in accordance with some
timings which in turn controls the execution process

Register stores data and result and speeds up the
operation
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COMPUTER FUNCTIONAL UNITS..
 MEMORY
 Stores
 Two

data, results, Instruction
class of storage
(i) Primary (ii) Secondary
 Two
types

RAM or R/W memory and

ROM read only memory
 ROM
is used to store data and program which is not
going to change.
 Secondary
storage
storage is used for bulk storage or mass
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COMPUTER FUNCTIONS

Data processing

Data may take a wide variety of forms and the range of
processing requirements is broad

Data storage


Short-term or Long-term
Data movement

Input-output (I/O) via peripheral

Data communications –over longer distances, or from a
remote device

Control

A control unit manages the computer’s resources
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COMPUTER ARCHITECTURE AND ORGANIZATION
 Computer

organization
operational units and their interconnections
that realize the architectural specifications

Organizational attributes include:

Hardware details transparent to the programmer

control signals


interfaces between the computer and peripherals
memory technology used
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COMPUTER ARCHITECTURE AND ORGANIZATION
 Computer

architecture
Attributes of a system visible to the programmer and
have a direct impact on the logical execution of a
program

Architectural attributes includes:

Instruction set,

number of bits used to represent various data types,

I/O mechanisms,

techniques for addressing memory
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INSTRUCTION SET ARCHITECTURE



A term that is often used interchangeably with computer
architecture
is the attributes of a computing system as seen by the
programmer
It deals with

The Instruction Set (what operations can be performed?)

The Instruction Format (how are instructions
specified?)

Data storage (where is data located?)

Addressing Modes (how is data accessed?)

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Exceptional Conditions (what happens if something
goes wrong?)
MACHINE ORGANIZATION

the view of the computer that is seen by the logic designer.

It deals with

Capabilities & performance characteristics of functional
units (e.g., registers, ALU, shifters, etc.).


Ways of functional unit interconnection

How information flows between components

Logic and means by which information flow is controlled

Coordination of functional units to realize the ISA
Typically the machine organization is designed to meet a
given instruction set architecture.
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GENERAL COMPUTER ORGANIZATION
Von Neumann
Machine
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INTERNAL BUS ORGANIZATION
Von Neumann
Machine
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CATEGORIES OF COMPUTER
 Computers
are classified based on the
parameters like

Speed of operation

Cost

Computational power

Type of application
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CATEGORIES OF COMPUTER CONT..
o Based on size and computing power
•Microcomputers (Personal Computer)
•Workstations
•Minicomputers
•Mainframes
•Supercomputers
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CATEGORIES OF COMPUTERS CONT..
Personal computer

Processing & storage units, visual display &
audio units, keyboards

Storage media‐Hard disks, CD‐ROMs

Eg: Personal computers which is used in
homes and offices

+ : Cost effective, easy to operate, suitable for
general purpose educational or business
application
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CATEGORIES OF COMPUTERS CONT..
Work stations

More computational power than PC

Costlier

Used to solve complex problems which
arises in engineering application
(graphics, CAD/CAM etc)
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CATEGORIES OF COMPUTERS CONT..
Minicomputers

a computer of medium power, more
than a microcomputer but less than a
mainframe.
Mainframe

data processing in large organization

referred as servers or super computers
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CATEGORIES OF COMPUTERS CONT..
Super computers

Faster than mainframes

Helps in calculating large scale numerical
and algorithm calculation in short span of
time

Used for aircraft design and testing,
military application and weather
forecasting
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HISTORY OF COMPUTER

Modern computers result from 2 streams of
evolution
 Mechanization of arithmetic calculating machines
(hardware)
 Concept of stored programs process control
(software )
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HISTORY OF COMPUTER – MECHANICAL ERA
 The abacus
 origin unknown
 used by the Chinese 3 to 4 thousand years ago
 Blasé Pascal (1623-1662)
 1642 - Pascal’s Adder
 1st mechanized adding machine
 gears and wheels
 add and subtract
 inaccurate
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HISTORY OF COMPUTER – MECHANICAL ERA
 Gottfried Wilhelm von Leibniz (1646-1716)
 1670’s - Leibniz calculator
• add, subtract, multiply, divide
• more reliable and accurate
• still inaccurate
• he also invented calculus
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HISTORY OF COMPUTER – MECHANICAL ERA
 Joseph Marie Jacquard (1752-1834)
 1800 - Jacquard’s Loom
 weaving loom
 metal punch cards to position threads for the
weaving process
 within the decade, 11,000 used in France
 may have been 1st case of unemployment
caused by automation
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HISTORY OF COMPUTER - MECHANICAL ERA
 Herman Hollerith (1860-1929)
 designed a machine that used electric charges to read
info off of punch cards
 for use in 1890 US census
 store and process census data
on punched cards
 started his own company in 1896
 in 1924 that company became International Business
Machines Corporation or IBM
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HISTORY OF COMPUTER –
1822-33 - Difference Engine
 compute polynomials for math tables
 abandoned, wasn’t precise
1830-71 - Analytical Engine
 designed but never completed, ahead of its time
 Mill - arithmetic computations
 Store - store data and results
 Operation cards - program instructions
 Variable cards - select memory location for ops
 Output - printer or punch cards
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HISTORY OF COMPUTER – ELECTROMECHANICAL
1939-42 - ABC
 John Atanasoff and

Clifford Berry (Iowa State)
 small scale - 300 vacuum
tubes
1944 - Mark I
 electromechanical computer
 Howard Aiken (Harvard U.)
 first real analytical engine
 based on relays
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HISTORY OF COMPUTER – ELECTRONIC
Electronic Numerical Integrator and Calculator
ENIAC (1946)
 Best known as first fully electronic computer
 18,000 vacuum tubes
 1,500 relays
 20 x 40 foot room
 low reliability, lots of
power, air conditioning
 Grace Hopper
 debugging it
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HISTORY OF COMPUTER – VON NEUMANN (1946)
 1946 - John von Neumann (Princeton)
 Developed stored program concept
 both programs and data stored in same memory
 Modern computers said to use von Neumann
architecture
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