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4CS107 Computer Organization & Architecture

UNIT – I

Lecture 01: Introduction

[ Computer Organization vs. Computer

Architecture; Structural/Functional View of
Computer ]

Dr. Suddhasil De

Unit-I Outcomes
1: UO-(Kn/De) (Knowledge/Define):
able to define terminologies related to computer organization
and architecture, leading to course outcome CO-[Kn/Rll];
2: UO-(Kn/Ru) (Knowledge/Reproduce):
able to reproduce concepts and approaches in design of CPU and
its components based on operations supported, leading to
course outcome CO-[Kn/Rll];
3: UO-(Cm/El) (Comprehension/Explain):
able to explain various design aspects of computer systems in
terms of computer organization and architecture, leading to
course outcome CO-[Cm/Ic];
CS107 (Computer Organization & Architecture) Dept. of CSE, NITP Dr. Suddhasil De
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Unit-I Outcomes
4: UO-(Ap/Sh) (Application/Show):
able to show complying of ISA for a CPU with different user
programs, leading to course outcome CO-[Ap/Ay].
5: UO-(Ap/Sv) (Application/Solve):
able to solve numerical problems related to fundamental
arithmetic operations supported by CPU and design problems
related to ISA and microprogramming, leading to course
outcome CO-[Ap/Sv].

CS107 (Computer Organization & Architecture) Dept. of CSE, NITP Dr. Suddhasil De
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Mapping: Unit-I Outcomes to Course Outcomes

• UO-(Kn/De)  CO-[Kn/Rll].
• UO-(Kn/Ru)  CO-[Kn/Rll].
• UO-(Cm/El)  CO-[Cm/Ic].
• UO-(Ap/Sh)  CO-[Ap/Ay].
• UO-(Ap/Sv)  CO-[Ap/Sv].

CS107 (Computer Organization & Architecture) Dept. of CSE, NITP Dr. Suddhasil De
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Lecture-1 Outcomes, and Mapping to Unit-I Outcomes

1: LO-(De):
able to define basic terms, including computer organization,
computer architecture, structural and functional views of CPU,
leading to unit outcome UO-(Kn/De);
2: LO-(Lt):
able to list differences between computer organization and
architecture in structural and functional views of computer sys-
-tem components, leading to unit outcome UO-(Kn/Ru).
Mapping:
• LO-(De)  UO-(Kn/De).
• LO-(Lt)  UO-(Kn/Ru).
CS107 (Computer Organization & Architecture) Dept. of CSE, NITP Dr. Suddhasil De
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Computer Organization and Architecture

• Computer Organization and Architecture: field of study for

selecting and interconnecting hardware components to create
computer systems that satisfying goals in functional performance
and cost.

Computer Organization Computer Architecture

CS107 (Computer Organization & Architecture) Dept. of CSE, NITP Dr. Suddhasil De
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Computer Architecture

• Computer Architecture: set of attributes of computer system,

visible to programmer (or software designer), and having direct
effect on logical execution of program.[Ref]
• Architectural attributes: instruction set, data formats (i.e. number
of bits to represent various data types, like numbers, characters
etc.), I/O mechanisms, memory addressing techniques etc.
• Example of architectural design issue:
whether a computer system should include a multiply instruction.

[Ref: William Stallings, Computer Organization and Architecture: Designing for Performance, Tenth edition, Pearson Education, 2016.]
CS107 (Computer Organization & Architecture) Dept. of CSE, NITP Dr. Suddhasil De
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Computer Organization

• Computer organization: operational units & their interconnections

to realize architectural specifications.
• Organizational attributes: hardware details (such as control
signals, interfaces between computer and peripherals, memory
technology used etc.) transparent to programmer.
• Example of organizational issue:
whether multiply instruction implemented by (i) special multiplier
unit, or (ii) mechanism for repeated use of adder unit of system.
[design approaches based on (i) anticipated frequency of use of multiply instruction,
(ii) relative speed of approaches, (iii) cost and physical size of special multiply unit]
CS107 (Computer Organization & Architecture) Dept. of CSE, NITP Dr. Suddhasil De
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Organization vs. Architecture

Computer Architecture Computer Organization

Programmer’s (or software Transparent from programmer (e.g.
designer’s) view (e.g. programmer programmer not aware of addition’s
to be aware of used instruction set). implementation in hardware).
Comprised of logic (i.e. instruction Comprised of physical components
set, addressing modes, data (i.e. circuit design, adders, signals,
formats, principle of operation, peripherals etc.)
registers used, interrupts etc.)
Deals with “what to do?” (like, Deals with “how to do?” (like,
instruction set). implementation of architecture).

CS107 (Computer Organization & Architecture) Dept. of CSE, NITP Dr. Suddhasil De
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Computer Organization and Architecture

• Computer organization and architecture:

(i) art of determining (functional) needs of user of a structure
(here, computer system), and Computer Architecture

(ii) then designing the system to meet such needs as effectively

as possible within economic and technological constraints.

Computer Organization

[Ref: W. Buchholz eds., Planning a Computer System: Project Stretch, Chapter 2, McGraw-Hill, 1962.]
CS107 (Computer Organization & Architecture) Dept. of CSE, NITP Dr. Suddhasil De
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Structure and Function of Computer

• Computer system: hierarchical system.

• Hierarchical system: set of interrelated subsystems (in multiple
levels), each of which, in turn, is hierarchical in structure, until
some lowest level of elementary subsystem reached.
• Significance of hierarchical nature of computer system:
important from both organization and architecture perspectives.

CS107 (Computer Organization & Architecture) Dept. of CSE, NITP Dr. Suddhasil De
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Structure and Function of Computer

• Organization perspective of hierarchical computer system:

• to deal with a particular level of system at a time;
• in that level, system viewed as a set of components and their
interrelationships (i.e. structure), as well as operation of individual
component as part of structure (i.e. function).

CS107 (Computer Organization & Architecture) Dept. of CSE, NITP Dr. Suddhasil De
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Structure and Function of Computer

• Architecture perspective of hierarchical computer system:

• describing system behavior by: (i) starting at bottom and building
a complete description (i.e. bottom-up approach), or (ii) beginning
with top view and decomposing system into its subparts (i.e. top-
down approach);
• In top-down approach, description beginning with major
components of computer, describing their structure and function,
and then proceeding to successively lower layers of hierarchy;
• system behavior at each level depending only on a simplified,
abstracted characterization of the system at next lower level.
CS107 (Computer Organization & Architecture) Dept. of CSE, NITP Dr. Suddhasil De
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Structure and Function of Computer

• Top-down description of computer system preferred, because:

(i) clearest description possible, and
(ii) most effective when studying computer architecture.

CS107 (Computer Organization & Architecture) Dept. of CSE, NITP Dr. Suddhasil De
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Functional View of Computer

[Ref: William Stallings, Computer Organization and Architecture: Designing for Performance, Pearson Education, Tenth edition, 2016.]
CS107 (Computer Organization & Architecture) Dept. of CSE, NITP Dr. Suddhasil De
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Functional View of Computer

• Four basic functions that computer can perform:

a. Data processing: to process data;
• for wide variety of data and broad range of processing
requirements, only few fundamental methods or types of data
processing exist.
b. Data storage: to store data;
• short-term data storage function: for data being processed;
• long-term data storage function: files of data stored for
subsequent retrieval and update.

CS107 (Computer Organization & Architecture) Dept. of CSE, NITP Dr. Suddhasil De
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Functional View of Computer

c. Data movement: to move data between computer and outside

world;
• computer’s attached devices (that create operating environment)
serving as sources or destinations of data;
• when data received from or delivered to directly-connected
device, that process of data movement is known as input-output
(I/O), and device is referred to as peripheral;
• when data moved over longer distances, to/from remote (or
remotely-connected) device, that process is known as data
communications.
CS107 (Computer Organization & Architecture) Dept. of CSE, NITP Dr. Suddhasil De
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Functional View of Computer

d. Control: to control of these three functions of computer;

• within computer, control unit managing computer’s resources and
orchestrating performance of its functional parts in response to
instructions of user programs;
• control ultimately exercised by individual(s), who provide
computer with instructions.

CS107 (Computer Organization & Architecture) Dept. of CSE, NITP Dr. Suddhasil De
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Functional View of Computer

• Functionally, four types of operations possible:

1. Functioning as data movement device:
simply transferring data from one
peripheral or communication line to
another.

[Ref: William Stallings, Computer Organization and Architecture: Designing for Performance, Pearson Education, Tenth edition, 2016.]
CS107 (Computer Organization & Architecture) Dept. of CSE, NITP Dr. Suddhasil De
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Functional View of Computer

• Functionally, four types of operations possible:

2. Functioning as data storage device:
data transferred from external environment
to computer’s storage (i.e. read) and
vice versa (i.e. write).

[Ref: William Stallings, Computer Organization and Architecture: Designing for Performance, Pearson Education, Tenth edition, 2016.]
CS107 (Computer Organization & Architecture) Dept. of CSE, NITP Dr. Suddhasil De
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Functional View of Computer

• Functionally, four types of operations possible:

3. Functioning as data processing device:
operations on data in storage.

[Ref: William Stallings, Computer Organization and Architecture: Designing for Performance, Pearson Education, Tenth edition, 2016.]
CS107 (Computer Organization & Architecture) Dept. of CSE, NITP Dr. Suddhasil De
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Functional View of Computer

• Functionally, four types of operations possible:

4. Functioning as data processing device:
operations en route between storage and
external environment.

[Ref: William Stallings, Computer Organization and Architecture: Designing for Performance, Pearson Education, Tenth edition, 2016.]
CS107 (Computer Organization & Architecture) Dept. of CSE, NITP Dr. Suddhasil De
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Structural View of Computer: External

• Computer interacting with

its external environment
(i.e. linkages to external
environment): classified as,
(i) peripheral devices, or
(ii) communication lines.

[Ref: William Stallings, Computer Organization and Architecture: Designing for Performance, Pearson Education, Tenth edition, 2016.]
CS107 (Computer Organization & Architecture) Dept. of CSE, NITP Dr. Suddhasil De
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Structural View of Computer: Internal

• Four main internal structural

components:
1. Central processing unit (CPU);
2. Main memory;
3. I/O;
4. System bus.

[Ref: William Stallings, Computer Organization and Architecture: Designing for Performance, Pearson Education, Tenth edition, 2016.]
CS107 (Computer Organization & Architecture) Dept. of CSE, NITP Dr. Suddhasil De
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Structural View of Computer

• Four main internal structural components:

1. Central processing unit (CPU): controlling operation of computer
and performing its data processing functions; often referred as
processor.
• Earlier computers having single processor; recently, multiple
processors being used in single computer.
2. Main memory: storing data.
3. I/O: moving data between computer and its external
environment.

CS107 (Computer Organization & Architecture) Dept. of CSE, NITP Dr. Suddhasil De
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Structural View of Computer

• Four main internal structural components:

4. System bus: interconnecting mechanism for communication
among CPU, main memory and I/O., and consisting of
conducting wires to which other components attach.

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Structural View of Computer

• CPU: most complex component of computer.

• Major structural components of CPU:
• Control unit: controlling operation of CPU, thus controlling entire
computer.
• Arithmetic and Logic unit (ALU): performing computer’s data
processing functions.
• Registers: providing storage internal to CPU.
• CPU interconnection: mechanism for communication among
control unit, ALU and registers.

CS107 (Computer Organization & Architecture) Dept. of CSE, NITP Dr. Suddhasil De
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Structural View of Computer

• Several approaches for implementation of CPU’s control unit.

• Common approach: microprogrammed implementation.
• Microprogrammed control unit: operate by executing micro-
-instructions that define functionality of control unit.
• Structure of microprogrammed control unit:
• Sequencing logic;
• Control unit registers and decoders;
• Control memory.

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Summary

• Focus: Significance of organization and architecture;

Structural/functional view of computer.
• Introduction to computer organization and architecture.
• Computer architecture and its range.
• Computer organization and its property.
• Distinguishing between these two terms.
• Structural and functional viewpoints of computer.
• Basic functions of computer, and corresponding operations.
• Fundamental structures of computer, with their hierarchical
decompositions.

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References
1. William Stallings, Computer Organization and Architecture: Designing for
Performance, Pearson Education, Tenth edition, 2016.
2. Andrew S. Tanenbaum, Todd Austin, Structured Computer Organization,
Pearson Education, Sixth edition, 2013.
3. John L. Hennessy, David A. Patterson, Computer Architecture: A Quantitative
Approach, Morgan Kaufmann, Sixth edition, 2017.
4. David A. Patterson, John L. Hennessy, Computer Organization and Design: The
Hardware/Software Interface, Morgan Kaufmann, Fifth edition, 2014.

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