ECE 3143: -
Computer Architecture and
Organization
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Organization and architecture
Why we study computer organization and
architecture?
– Evaluate computer system performance.
– Understand time, space, and price tradeoffs.
– Design better programs, including system
software such as compilers, and operating
systems.
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Organization and…cont’d
• Computer architecture
– Functional operation of the individual HW units within a
computer system.
– Logical aspects of system implementation as seen by the
programmer.
• E.g., instruction sets, instruction formats, data types,
addressing modes.
– How do I design a computer?
– The structures of a computer family not the specific
implementation, just like the architecture of a house might
be described as Victorian, villa, etc.
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Organization and…cont’d
• Computer organization
– The internal arrangements of a computers, or how
features are implemented.
– Ways in which these components are interconnected
– Includes all physical aspects of computer systems.
• E.g., circuit design, control signals, memory types.
– How does a computer work?
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Organization and…cont’d
Example, Including multiply instruction
• It is an architectural design issue whether a computer will
have a multiply instruction.
• It is an organizational issue whether that instruction will be
implemented by a special multiply unit or by a mechanism
that makes repeated use of the add unit of the system.
• The organizational decision may be based on the predicted
frequency of use of the multiply instruction, the relative
speed of the two approaches, and the cost and physical
size of a special multiply unit.
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Structure and Function
• A computer is a complex system; contain millions of electronic
components. How, then, can one clearly describe them?
• Structure
– The way in which components relate
to each other
• Function
– The operation of individual
components as part of the structure
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Function
A computer can perform
four basic functions:
● Data processing
● Data storage
● Data movement
● Control
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Operations(a) Operations(b)
Data movement Data storage
• It can also function as a data storage
• The computer as a data movement device.
device. Data transferred from the external
simply transferring data from environment to computer storage
one peripheral or (read) and vice versa (write).
communication line to another. 8
Operations(c) Operations (d)
Data movement Control
• Data processing, on data in storage • Between storage and the external
environment
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The internal structure of a computer
CPU – controls the operation and
performs its data processing.
Main Memory – stores data
I/O – moves data between the
computer and its external
environment
System Interconnection – some
mechanism that provides
communication among CPU, main
memory, and I/O
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CPU
• Control Unit
Major structural components:
– Controls the operation of the CPU and
hence the computer
– Arithmetic and Logic Unit (ALU)
– Performs the computer’s data
processing function
– Registers
– Provide storage internal to the CPU
– CPU Interconnection
– Some mechanism that provides for
communication among the control unit,
ALU, and registers
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COMPUTER EVOLUTION
• The First Generation: Vacuum Tube Computers (1945
- 1953)
– Electronic Numerical Integrator and Computer
(ENIAC)
– Solved systems of linear equations.
– The ENIAC was the first general-purpose computer.
• Shorten a computational time from 20hrs to
30secs of pascal.
• impractical because the vacuum tubes would
burn out frequently.
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ENIAC
ENIAC ……cont’d
• On the ENIAC, all programming was done at
the digital logic level.
• Programming the computer involved moving
plugs and wires.
Configuring the ENIAC to solve a “simple” problem
required many days labor by skilled technicians.
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The von Neumann Model
• Stored Program concept
• Main memory storing
programs and data
• Control unit interpreting
instructions from memory
and executing
• These computers employ
a fetch-decode-execute
cycle to run programs as
follows . . .
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The von Neumann Model
• The control unit fetches the next instruction from memory using
the program counter to determine where the instruction is located.
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The von Neumann Model
• The instruction is decoded into a language that the ALU
can understand.
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The von Neumann Model
• Any data operands required to execute the instruction
are fetched from memory and placed into registers within
the CPU.
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The von Neumann Model
• The ALU executes the instruction and places results in
registers or memory.
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Evolution cont’d
• The Second Generation: Transistorized Computers
(1954 - 1965)
– CDC 6600 the world first computer
– 10 million instructins/sec = 10MHZ
– 128kilowords of main memory
• $10 million
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Evolution cont’d
• The Third Generation: Integrated Circuit
Computers (1965 - 1980)
• Small scale integration (SSI), Medium scale integration
(MSI)- Large scale integration (LSI)
• 3,000 - 100,000 devices on a chip
CDC 6600 version – Cray-1 produced
Execute 160 million ins/sec = 160 MHZ
8MB of memory
$ 8.8million
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Evolution cont’d
• The Fourth Generation: VLSI Computers (1980
- ????)
– Very large scale integrated circuits (VLSI) have more
than 100,000 components per chip.
– Enabled the creation of microprocessors.
• Versions, such as the 8080, 8086, and 8088 produced
the idea of “personal computing.”
– home computing
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