Computer Architecture and Organization (CS-507)

Lecture 1Introduction

Muhammad Zeeshan Haider Ali

Lecturer

ISP. Multan

ali.zeeshan04@gmail.com

https://zeeshanaliatisp.wordpress.com/

Course Objectives

• To learn the organizational paradigms that determine the capabilities and performance of computer systems

• To understand the interactions between the computer’s architecture and its software so that

– future software designers (compiler writers, operating system designers, database programmers, …) can achieve the best cost-performance trade-offs

– future architects understand the effects of their design choices on software applications

– future researchers develop understanding of various issues in computer architecture to formulate possible research problems

• To know some of the advanced design features on modern processors that boost the performance

• To understand contemporary design issues and how to conduct a trade-off among the various design objectives

Reference Material

• Computer Organization and Architecture 8e by William Stallings

• Computer Organization And Design The hardware and software interface by David A Patterson and John L Hennessy 5th Edition 2014

• The intel microprocessor Barry B Brey 8th edition

Marking Criteria:

• Mid = 25 Marks

• Final = 50 Marks

• Attendance = 10 Marks

• Sessional = 15 Marks

• Sessional Criteria

4 Assignments (2 Marks)

4 Quizzes (2 Marks)

Presentation (5 Marks)

Class Participation, Attitude (3 Marks)

Attendance, Exam Result (3 Marks)

Teaching Style and Philosophy

• My role is to– Facilitate and guide the students to the fundamental concepts– Make it simple and elaborate with examples– Relate as much as possible to available products– Prepare class notes to be as rich and comprehensive as possible

• Your role is to– Focus on understanding and digesting the concept– Do not worry about the grade more than concepts; you are a

professional !!– Slow down me if you do not understand and raise questions– Be prepared to answer an oral quiz, when you get involved in a

side talk

Motivation

• Computer systems are responsible of 10-15% of the gross product of the world

• WWW, ATM, Cashless society, anywhere computing, DNA mapping, Quantum computing, … are among the applications that were economically infeasible and recently have become practical

• Wearable networks, implanted computers, automated intelligent highways… are next computer science fiction on their way to become a reality

• Computer architecture has been at the core of such technological development and is still on a forward move

Today’s Agenda

• Introduction to Computer Architecture.

• Fundamentals of Computer Design

• Performance Measurements.

ORGANIZATIONAND ARCHITECTURE

➢ Computer architecture refers to those attributes of a system

visible to a programmer or, put another way, those attributes that

have a direct impact on the logical execution of a program.

➢ Computer organization refers to the operational units and their

interconnections that realize the architectural specifications.

Continue…...➢ Examples of architectural attributes include the

instruction set, the number of bits used to represent

various data types (e.g., numbers, characters), I/O

mechanisms, and techniques for addressing memory.

Organizational attributes include those hardware details

transparent to the programmer, such as control signals;

interfaces between the computer and peripherals; and

the memory technology used.

Continue…➢ For example, 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

➢ In a class of computers called microcomputers, the

relationship between architecture and organization is

very close. Changes in technology not only influence

organization but also result in the introduction of more

powerful and more complex architectures.

Computer Architecture - Definition

• Computer Architecture = ISA + MO

• Instruction Set Architecture– What the executable can “see” as underlying hardware

– Logical View

• Machine Organization– How the hardware implements ISA ?

– Physical View

Computer Architecture – Changing Definition

•1950s to 1960s: Computer Architecture Course:

• Computer Arithmetic

•1970s to mid 1980s: Computer Architecture Course: • Instruction Set Design, especially ISA appropriate for compilers

•1990s: Computer Architecture Course:

• Design of CPU, memory system, I/O system, Multiprocessors, Networks

•2000s: Computer Architecture Course:• Non Von-Neumann architectures, Reconfiguration

•Today’s: DNA Computing, Quantum Computing ????

“What” is Computer Architecture ?

• Coordination of many levels of abstraction

• Under a rapidly changing set of forces

• Design, Measurement, and Evaluation

I/O systemInstr. Set Proc.

Compiler

OperatingSystem

Application

Digital Design

Circuit Design

Instruction SetArchitecture

Firmware

Datapath & Control

Layout

ISA: Critical Interface

instruction set

software

hardware

STRUCTURE AND FUNCTION

The way in which the components are➢ Structure:interrelated

➢ Function: The operation of each individual component aspart of the structure

➢ The computer system will be described from the top down.We begin with the major components of a computer,describing their structure and function, and proceed tosuccessively lower layers of the hierarchy.

Continue……

Continue…

➢ Above figure depicts the basic functions that a computer canperform.

In general terms, there are only four:

➢ Data processing

➢ Data storage

➢ Data movement

➢ Control

Structural units

➢ Top-Level Structure of computer:

Continue…➢ But in general term there four structural units of computer whichare:

➢ Central processing unit (CPU): Controls the operation of the computer and

performs its data processing functions; often simply referred to as

processor.

➢ Main memory: Stores data.

➢ I/O: Moves data between the computer and its externalenvironment.

➢ System interconnection: Some mechanism that provides for

communication among CPU, main memory, and I/O. A common example of

system interconnection is by means of a system bus, consisting of a number

of conducting wires to which all the other components attach.

Continue…➢ The most complex unit/component is CPU

➢ Internal units/components of CPU are:

▪ Control unit: Controls the operation of the CPU and hence

the computer

▪ Arithmetic and logic unit (ALU): Performs the computer’s

data processing functions

▪ Registers: Provides storage internal to the CPU

▪ CPU interconnection: Some mechanism that provides for

communication among the control unit, ALU, and registers

Factors affecting ISA ???

Computer

Architecture

Technology ProgrammingLanguages

Operating

Systems

History

Applications

Cleverness

Impact of changing ISA

• Early 1990’s Apple switched instruction set architecture of the Macintosh

– From Motorola 68000-based machines

– To PowerPC architecture

• Intel 80x86 Family: many implementations of same architecture

– program written in 1978 for 8086 can be run on latest Pentium chip

The Big Picture

Since 1946 all computers have had 5 components!!!

Control

Datapath

Memory

Processor

Input

Output

The Role of Performance

Performance Metrics

• Response Time

– Delay between start end end time of a task

• Throughput

– Numbers of tasks per given time

• New: Power/Energy

– Energy per task, power

Examples (Throughput/Performance)

• Replace the processor with a faster version?

– 3.8 GHz instead of 3.2 GHz

• Add an additional processor to a system?

– Core Duo instead of P4

Measuring Performance

• Wall-clock time –or- Total Execution Time

• CPU Time

– User Time

– System Time

Relating the Metrics

• Performance = 1/Execution Time

• CPU Execution Time = CPU clock cycles for program x Clock cycle time

• CPU clock cycles = Instructions for a program x Average clock cycles per Instruction

Technology Trends

Big Fish Eating Little Fish

In reality:

Technology Trends

PCWork-

stationMini-

computer

Mainframe

Mini-

supercomputerSupercomputer

Massively

Parallel

Processors

1988 Computer Food Chain

Technology Trends

1998 Computer Food Chain

PCWork-

station

Mainframe

Supercomputer

Mini-

supercomputerClusters

Mini-

computer

Now who is eating whom?

Server