INSY2041 Computer Organization and Architecture
Chapter One: Digital logic and digital systems
lecture 01: Overview and history of computer architecture
Summer Jul 24, 2017
Department of Information System College of Computing
1 Debre Berhan University
Belesti Y.
Belesti Yenegeta, DBU, College of Computing
2 What is expected of you?
Attend class and participate
Be a hero ask stupid questions
Do the work the homework and project are more than half your
grade for a reason, doing them is the heart of the course
Things arent always as simple as they look the devil is in the
details
Dont procrastinate
Take initiative to follow up on your interests
Dont cheat: follow code of conduct
Belesti Yenegeta, DBU, College of Computing
3 Why Study Computer Architecture and Organization?
The computer lies at the heart of computing.
Without it most of the computing disciplines today would be a
branch of theoretical mathematics.
To be a professional in any field of computing today, one should not
regard the computer as just a black box that executes programs by
magic.
All students of computing should acquire some understanding and
appreciation of a computers system functional components, their
characteristics, their performance, and their interactions.
You need to understand computer architecture in order to structure a
program so that it runs more efficiently on a real machine.
Belesti Yenegeta, DBU, College of Computing
4 Contd
In selecting a system to use, you should be able to understand the
tradeoff among various components, such as CPU clock speed vs
memory size.
Computer architecture is concerned with all aspects of the design
and organization of the CPU and the integration of the CPU into the
computer system itself.
Architecture extends upward into computer software because a
processors architecture must cooperate with the operating system
and system software.
It is difficult to design an operating system well without knowledge
of the underlying architecture.
Belesti Yenegeta, DBU, College of Computing
5 Objectives
Differentiate computer organization and computer architecture
Differentiate between computer structure and computer function
Explain the main functions of a computer
List and briefly define the main structural components of a computer
List and briefly define the main structural components of a
processor
Know the course scope
Belesti Yenegeta, DBU, College of Computing
6 Architecture and Organization
Architecture refers to those attributes of a system visible to the
programmer, or put another way, those attributes that have a direct impact
on the logical execution of a program.
Instruction set, number of bits used to represent various data types
(e.g., numbers, characters), I/O mechanisms, addressing techniques
e.g. Is there a multiply instruction?
Organization refers to the operational units and their interconnections that
realize the architectural specifications. It is how features are implemented
Hardware details transparent to the programmer, such as Control
signals, interfaces, memory technology
e.g. Is there a hardware multiply unit or is it done by repeated
addition?
Belesti Yenegeta, DBU, College of Computing
7 Contd
All Intel x86 family share the same basic architecture
The IBM System/370 family share the same basic
architecture
This gives code compatibility
At least backwards
Organization differs between different versions
Belesti Yenegeta, DBU, College of Computing
8 Structure and function
Structure refers to the way in which components relate to each
other.
Function is the operation of individual components as part of
the structure.
In terms of description, we have two choices: starting at the
bottom and building up to a complete description, or beginning
with a top view and decomposing the system into subparts.
Evidence from a number of field suggests that the top-down
approach is the clearest and most effective [WEIN75]
Belesti Yenegeta, DBU, College of Computing
9 Function
All computer functions are:
Data processing
Data storage
Data movement
Control
Belesti Yenegeta, DBU, College of Computing
10 Functional view of the computer
Belesti Yenegeta, DBU, College of Computing
11 Operations - data movement
Belesti Yenegeta, DBU, College of Computing
12 Operations - storage
Belesti Yenegeta, DBU, College of Computing
13 Operations processing from/to storage
Belesti Yenegeta, DBU, College of Computing
14 Operations processing from storage to I/O
Belesti Yenegeta, DBU, College of Computing
15 Structure Top Level
Peripherals
Computer
CPU Main
Memory
Computer Systems
interconnection
Input
Output
Communication lines
Belesti Yenegeta, DBU, College of Computing
16 Structure - The CPU
CPU
Arithmetic
Registers and
Computer Logic Unit
I/O
Internal CPU
System CPU Interconnection
Bus
Memory
Control
Unit
Belesti Yenegeta, DBU, College of Computing
17 Structure - The Control Unit
Control Unit
Sequencing
Logic
CPU
ALU Control Unit
Internal
Control Registers and
Unit
Bus Decoders
Registers
Control
Memory
Belesti Yenegeta, DBU, College of Computing
18 Course Scopecntd
High Level Language Level
(e.g. C++, Java)
Assembly Language Level
Operating System Level Software
(e.g. Windows, Linux, iOS)
Instruction Set Architecture
Level (computer instructions)
Microarchitecture Level
(registers, ALU, control unit, memory)
Digital Logic Level Hardware
(gates, flip-flops)
Belesti Yenegeta, DBU, College of Computing
