Lecture 1
Introduction to
Computer Organization & Architecture
Lecture Duration: 2 Hours
Lecture Overview
 Course description
 Chapter 1 : Introduction
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Overview of computer organization and architecture
The main components of a computer
An example system: wading through the jargon
Standards organizations
Historical development of computers
The computer level hierarchy
The Von Neumann model
Prepared by Dr. Hassan SALTI - 2012
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Course description (1/3)
 Course name
• T103 - Computer Organization and Architecture
 Course level
• Level 1 course
• Equivalent to 3 CH (Credit Hours)
 Assessment
• Continuous Assessment (CA) : 50%
- 1 TMA (Tutor Marked Assignment) : 20%
- 1 MTA (Mid-Term Assessment): 30%
• Final Exam: 50%
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Course description (2/3)
 Success Requirements
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Attend at least 5/7 lectures (≈70% attendance)
Get at least 20/50 on the CA (TMA + MTA)
Get at least 20/50 on the Final Exam
Get at least a total of 50/100 (TMA + MTA + Final)
 Course Lectures
• Number of lectures: 7 lectures
• Bi-Weekly lectures: One lecture every 2 weeks
• Lecture duration : 2 Hours
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Course description (3/3)
 Reference Book
• The essentials of Computer Organization and
Architecture, 2nd edition – Author: Linda Null and
Julia Lobur
 Topics to be covered
• History of computers, computers models, Binary
arithmetic, Boolean algebra, Digital logic,
Memory, …
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Lecture Overview
 Course description
 Chapter 1 : Introduction
•
•
•
•
•
•
•
Overview of computer organization and architecture
The main components of a computer
An example system: wading through the jargon
Standards organizations
Historical development of computers
The computer level hierarchy
The Von Neumann model
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Chapter 1: Introduction
Overview of computer organization and architecture (1/5)
 Some programs/algorithms are
today computationally
infeasible, why?
 Tomorrow, those could become
feasible, why?
 To understand why, we need to:
• see the program from the
computer’s point of view
• explore the “computer
organization and architecture”
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Chapter 1: Introduction
Overview of computer organization and architecture (2/5)
 What is computer organization and
architecture?
• In a computer system, hardware and many
software components are fundamentally related
• Computer organization and architecture help us
to understand how hardware and software
interact with each other
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Chapter 1: Introduction
Overview of computer organization and architecture (3/5)
 Computer organization?
• It encompasses all physical aspects of computer
systems.
- How components are connected together?
- How components interact with/talk to each other?
• It addresses issues such as
- Control signals, signaling methods
- Memory types, …
• It helps us to answer the question: How does a
computer work?
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Chapter 1: Introduction
Overview of computer organization and architecture (4/5)
 Computer architecture?
• It focuses on the structure and behavior of the
computer system
• It refers to the logical aspects of system
implementation as seen by the programmer.
• It includes many elements such as
- instruction sets and formats, data types, addressing
modes, number and type of registers, …
• It helps us to answer the question: How do I
design a computer?
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Chapter 1: Introduction
Overview of computer organization and architecture (5/5)
 Computer organization VS architecture?
• The distinction between computer organization
and computer architecture is not clear-cut.
• These are strongly interrelated and
interdependent.
• We can truly understand each of them only when
we comprehend both of them.
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Lecture Overview
 Course description
 Chapter 1 : Introduction
•
•
•
•
•
•
•
Overview of computer organization and architecture
The main components of a computer
An example system: wading through the jargon
Standards organizations
Historical development of computers
The computer level hierarchy
The Von Neumann model
Prepared by Dr. Hassan SALTI - 2012
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Chapter 1: Introduction
The main components of a computer (1/3)
 From Software to Hardware
• Computer scientists design algorithms
• Computer scientists implement an algorithm by
using high level programing language (Java, C,
etc.)
• Another algorithm runs this algorithm and
another one runs that algorithm and so on
• We finally get down to machine level
• Machine level can be thought of as an algorithm
implemented as an electronic device
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Chapter 1: Introduction
The main components of a computer (2/3)
 Principle of Equivalence of Hardware and
Software
Anything that can be done with software can also be done with
hardware, and anything that can be done with hardware can
also be done with software
 We implement an application in Hardware or
Software level?
• Our knowledge of computer organization and
architecture will help us to make the best choice
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Chapter 1: Introduction
The main components of a computer (3/3)
 Computer Hardware main components
• A processor to interpret and execute programs
• A memory to store both data and programs
• A mechanism for transferring data to and from
the outside world (Input/Output)
 Think of how a student sitting in class exhibits
the three components of a computer?
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Lecture Overview
 Course description
 Chapter 1 : Introduction
•
•
•
•
•
•
•
Overview of computer organization and architecture
The main components of a computer
An example system: wading through the jargon
Standards organizations
Historical development of computers
The computer level hierarchy
The Von Neumann model
Prepared by Dr. Hassan SALTI - 2012
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Chapter 1: Introduction
An example system: wading through the jargon (1/10)
The stated system is a wise buy?
Does it serve your needs?
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Chapter 1: Introduction
An example system: wading through the jargon (2/10)
 “64MB SDRAM”, “64-bit PCI sound card”,
“32KB L1cache”, …?
 Without having a handle on such terminology,
you would be hard-pressed to answer such
questions…
 The next few slides explain the content of the
advertisement (ad)
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Chapter 1: Introduction
An example system: wading through the jargon (3/10)
 A reminder (TU170):
•
•
•
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Computers do computations in base 2 (binary system)
A binary character is called a bit (0 or 1)
A byte is a set of 8 bits
“Bits, bytes, KB, MB, …” are used to measure the storage
capacity of a device (RAM, HDD, Flash memory, etc.)
• We use the below table to convert from one unit to another
 Example:
• 1KB = 210 = 1024 Bytes = 1024 x 8 bits = 8192 bits
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Chapter 1: Introduction
An example system: wading through the jargon (4/10)
 A reminder (TU170):
• The speed of a device is usually measured in Hz
(Hertz), KHz, MHz, …
- Example: Processor speeds are measured in MHz or GHz.
• The table in figure 1.2 (Slide 19) help us to convert
from one unit to another
- Example: 1MHz = 106 Hz =1,000,000 Hz
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Chapter 1: Introduction
An example system: wading through the jargon (5/10)
 Back to the advertisement (Slide 17)
 Pentium III 667 MHz?
• Pentium III : The microprocessor type
• 667 MHz: microprocessor’s clock speed
- Each microprocessor has a synchronization clock (it sends
electrical pulses)
- Here, the clock speed is 667 million electrical pulse per
second
- The number of instructions per second that a processor can
execute is proportionate to its clock speed (not equal to).
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Chapter 1: Introduction
An example system: wading through the jargon (6/10)
 133 MHz 64MB SDRAM?
• SDRAM: Main memory type, “Synchronous
Dynamic Random Access Memory”
• 133 MHz: Speed of the system bus (between the
memory and the microprocessor)
• 64 MB : Memory Capacity (64 x 220 x 8 bits =
536870912 bits)
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Chapter 1: Introduction
An example system: wading through the jargon (7/10)
 32KB L1 cache, 256KB L2 cache?
• Two cache memory to speed up the data transfer
between the main memory and the processor
• 32KB and 256KB are the capacity of level 1 (L1) and level 2
(L2) memory respectively
 30GB EIDE hard drive (7200 RPM)?
• 30GB: The capacity of the hard drive
• 7200 RPM: Speed of disk rotation is 7200 round per
minute
• EIDE: disk interface (connectivity with the rest of the
computer’s components). EIDE stands for Enhanced
Integrated Drive Electronics
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Chapter 1: Introduction
An example system: wading through the jargon (8/10)
 48X max variable CD-ROM?
• CD-ROM drive
• 48X: the maximum reading data rate the CD drive can
achieve (48 times the traditional audio CD data transfer
rate)
 2 USB ports, 1 serial port, 1 parallel port?
• Ports that allow movement of data to and from devices
external to the computer.
 19" monitor, .24mm AG, 1280 x 1024 at 85Hz?
• The monitor size (19”), resolution (1280 x 1024), refresh
rate (85Hz) and pixel size (0.24mm).
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Chapter 1: Introduction
An example system: wading through the jargon (9/10)
 Intel 3D AGP graphics card?
• Graphic interface for 3D graphics
• AGP stands for “Accelerated Graphics Port”
 56K PCI voice modem? 64-bit PCI sound
card?
• PCI : Dedicated I/O buses, PCI stands for “Peripherial
Component Interconnect
• PCI voice modem: for internet connection
• PCI sound card : for the system’s stereo speakers
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Chapter 1: Introduction
An example system: wading through the jargon (10/10)
 A look inside a computer
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Lecture Overview
 Course description
 Chapter 1 : Introduction
•
•
•
•
•
•
•
Overview of computer organization and architecture
The main components of a computer
An example system: wading through the jargon
Standards organizations
Historical development of computers
The computer level hierarchy
The Von Neumann model
Prepared by Dr. Hassan SALTI - 2012
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Chapter 1: Introduction
Standards organizations (1/3)
 Standards organizations?
• Number of government and industry
organizations
• Some standards-setting organizations are
consortia made up of industry leaders
• Aims
- Establish common guide lines for a particular type of
equipment
- Why? To ensure a “worldwide”1 interoperability
(compatibility)
1
The term “worldwide” is correct only when the organization and its standards are international
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Chapter 1: Introduction
Standards organizations (2/3)
 Some international standards organizations
• IEEE
- Institute of Electrical and Electronic Engineers
- sets standards for various computer components, signaling
protocols, and data representation
• ITU
- International Telecommunications Union
- Sets standards for telecommunications systems, including
telephone, telegraph, and data communication systems
• ISO
- International Standards Organization
- coordinates worldwide standards development
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Chapter 1: Introduction
Standards organizations (3/3)
 Other county(ies)-wide organizations
• ANSI: American National Standards Institute
• CEN: Comité Européenne de Normalisation
(European committee for standardization)
• BSI: British Standards Institution
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Lecture Overview
 Course description
 Chapter 1 : Introduction
•
•
•
•
•
•
•
Overview of computer organization and architecture
The main components of a computer
An example system: wading through the jargon
Standards organizations
Historical development of computers
The computer level hierarchy
The Von Neumann model
Prepared by Dr. Hassan SALTI - 2012
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Chapter 1: Introduction
Historical development of computers (1/6)
 To fully appreciate the computers of today, it
is helpful to understand how things got the
way they are.
 The evolution of computing machinery has
taken place over several centuries.
 In modern times computer evolution is
usually classified into four generations
according to the salient technology of the era.
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Chapter 1: Introduction
Historical development of computers (2/6)
 Generation Zero: Mechanical Calculating Machines (1642 – 1945)
• Use of mechanical technology to do calculations
• Suggest the use of binary number system rather than the decimal
number system

First Generation: Vacuum tube computers
(1945–1953)
• Use of electrical/electronic technology (much
faster than mechanical technology)
• Invent binary machines built from vacuum tubes
• Invent vaccum tubes diodes and triodes
• Disadvantages: Bulky systems, Power
consumption and heat dissipation.
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Chapter 1: Introduction
Historical development of computers (3/6)
 The Second Generation: Transistorized Computers
(1954–1965)
• Transistors revolutionize computers
- Transistors consume less power than vacuum tubes, are smaller,
and work more reliably,
- the circuitry in computers became smaller and more reliable.
 The Third Generation: Integrated Circuit Computers
(1965–1980)
• Integrating multiple transistors in a single
silicon/germanium chip
• Explosion in computer use
• Computers became faster, smaller, and cheaper, bringing
huge gains in processing power
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Chapter 1: Introduction
Historical development of computers (4/6)
 The Fourth Generation: VLSI Computers (>1980)
• More integration, more transistors on a single silicon chip (see the
table below)
• Computers became smaller: Appearance of micro-computers
• Increasing the processing power of all computers types (also
supercomputers and main frame computers)
Scale Integration
Number of components per chip
SSI: Small Scale Integration
10 – 100
MSI: Medium Scale Integration
100 – 1000
LSI: Large Scale Integration
1000 - 10000
VLSI: Very Large Scale Integration
> 10000
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Chapter 1: Introduction
Historical development of computers (5/6)
 Size comparison
Vacuum Tube
Transistor
Integrated circuit
chip
Integrated circuit
package
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Chapter 1: Introduction
Historical development of computers (6/6)
 Moore’s Law (Gordon Moore – Intel Founder, 1965)
• The density of transistors in an integrated circuit will
double every year
• The law hold for almost today (2012)!
 Rock’s Law (early Intel capitalist Arthur Rock)
• The cost of capital equipment to build semiconductors will
double every four years
 If Moore’s Law is to hold, Rock’s Law must fall or
computers must shift to a radically different
technology
 Research into new computing paradigms has been
proceeding in earnest during the last half decade
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Lecture Overview
 Course description
 Chapter 1 : Introduction
•
•
•
•
•
•
•
Overview of computer organization and architecture
The main components of a computer
An example system: wading through the jargon
Standards organizations
Historical development of computers
The computer level hierarchy
The Von Neumann model
Prepared by Dr. Hassan SALTI - 2012
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Chapter 1: Introduction
The computer level hierarchy (1/6)
 The user executes programs on a PC (Paint, word files,
games, etc.)
 The user is outside the computer! He uses input and
output devices to communicate with the computer.
 Now, what happens INSIDE the computer?
 To understand, we will use a “divide and conquer”
approach.
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Chapter 1: Introduction
The computer level hierarchy (2/6)
 Imagine the machine (computer) as a hierarchy
of levels, in which each level has a specific
function.
 The highest level – Level 6 – is the “user’s level”
• Level 6 is composed of applications
• User runs programs such as word processors,
graphics packages, or games.
 The lower levels are unseen by the user those
can be considered as “virtual machines”.
 Let us discover these “virtual machines”.
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Chapter 1: Introduction
The computer level hierarchy (3/6)
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Chapter 1: Introduction
The computer level hierarchy (4/6)
 Level 5: High-Level Language Level
• Consists of languages such as C, C++, FORTRAN, Lisp,
Pascal, and Prolog.
• Programmers write programs at this level.
• Compilers translates these languages to a language the
machine can understand (that lower levels could
understand): Assembly then machine languages.
 Level 4: Assembly Language Level
• More “machine dependent” language.
• Assembly language is then one to one translated to
machine language (one assembly language instruction is
translated to exactly one machine language instruction).
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Chapter 1: Introduction
The computer level hierarchy (5/6)
 Level 3: System Software Level
• Deals with operating system instructions (multiprogramming,
protecting memory, synchronizing processes, and various other
important functions)
• Instructions translated from assembly language to machine
language are passed through this level unmodified
 Level 2: Instruction Set Architecture (ISA), or Machine
Level
• Machine language recognized by the particular architecture of
the computer system
• Programs written in machine language can be executed directly
by the electronic circuits without any interpreters, translators,
or compilers.
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Chapter 1: Introduction
The computer level hierarchy (6/6)
 Level 1: The Control Level
• Is where a control unit do its job
- Receives machine instructions from the level above
- decodes and executes those instructions properly
- Moves data to where and when it should be
• The control unit interprets the machine
instructions
 Level 0: The Digital Logic Level
• is where we find the physical components of the
computer system: the gates and wires
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Lecture Overview
 Course description
 Chapter 1 : Introduction
•
•
•
•
•
•
•
Overview of computer organization and architecture
The main components of a computer
An example system: wading through the jargon
Standards organizations
Historical development of computers
The computer level hierarchy
The Von Neumann model
Prepared by Dr. Hassan SALTI - 2012
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Chapter 1: Introduction
The Von Neumann model (1/7)
 A computer architecture model published by a
famous Hungarian mathematician named John
von Neumann
 The idea is to store programs’ instructions inside
a main memory in order to avoid rewiring the
system each time it had a new problem to solve,
or an old one to debug.
 All stored-program computers have come to be
known as von Neumann systems using the von
Neumann architecture
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Chapter 1: Introduction
The Von Neumann model (2/7)
 The Von Neumann architecture is shown in Figure 1.4
– Slide 48
 It satisfies at least the following characteristics
• Consists of three hardware systems (see figure 1.4 – slide
48)
- A central processing unit (CPU) with a control unit, an arithmetic
logic unit (ALU), registers (small storage areas), and a program
counter;
- a main-memory system, which holds programs that control the
computer’s operation;
- and an I/O system.
• Capacity to carry out sequential instruction processing
• Contains a single path, between the main memory system
and the control unit of the CPU
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Chapter 1: Introduction
The Von Neumann model (3/7)
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Chapter 1: Introduction
The Von Neumann model (4/7)
 Program instructions are stored inside the
main memory
 The machine runs the programs sequentially
(instruction per instruction – machine
instruction)
 Each machine instruction is fetched, decoded
and executed during one cycle known as the
von Neumann execution cycle (also called the
fetch-decode-execute cycle)
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Chapter 1: Introduction
The Von Neumann model (5/7)
 One iteration of the cycle is as follows:
1. The control unit fetches the next program instruction
from the memory, using the program counter to
determine where the instruction is located.
2. The instruction is decoded into a language the ALU
can understand.
3. Any data operands required to execute the
instruction are fetched from memory and placed into
registers within the CPU.
4. The ALU executes the instruction and places the
results in registers or memory.
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Chapter 1: Introduction
The Von Neumann model (6/7)
1. Fetch
• PC indicates
the iteration
number
• CU fill the
instruction
register
Instruction 1
Instruction 2
Instruction 3
Data 1
2. Decode
• what ALU
should do
(add, multiply,
…)?
• Fill registers
with needed
data
Prepared by Dr. Hassan SALTI - 2012
Data 2
Instruction 3
Instruction 4
…
…
…
Instruction N
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Chapter 1: Introduction
The Von Neumann model (7/7)
3. Execute
• Execute the
instruction
• Place the
results in
registers or
memory
Instruction 1
Instruction 2
Instruction 3
Data 1
Data 2
Instruction 3
Instruction 4
Result
…
…
…
Instruction N
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Conclusion
Conclusion (1/1)
 This chapter has given you an overview of the
subject of computer architecture.
 You should now be sufficiently familiar with
general system structure to guide your studies
throughout the remainder of this course.
 Subsequent chapters will explore many of
these topics in great detail.
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End of lecture 1
Try to solve all exercises related to lecture 1