Chapter 1 Introduction

Objectives To explain the definition of computer architecture To discuss the history of computers To describe the von-neumann machine architecture To discuss how to measure the quality of a computer architecture and the factors that influence the success of a computer architecture To introduce the concept of computer as a hierarchical system using structure and functions To describe the functions of each component in a computer

Organization and architecture Architecture -- refers to those attributes of a system visible to a programmer or those attributes that have a direct impact on the logical execution of a program. - instruction set, number of bits used for data representation, I/O mechanism, addressing technique. Organization – refers to the operational unit and their interconnections that realize the architectural specification -- control signal, interface to peripherals, memory technology.

4 Computer Architecture  Instruction set design  Computer Interface  Compiler/System View  Machine Organization  Hardware components  Logic Designer’s View

What is a computer? A computer is a tool for solving problems (ex: perform arithmetic calculations) Requirements of a computer –process, store, moves, control 4 main functions performed by a computer –accepts ->process-> stores->produces

Computer Architecture Hayes: “The study of the structure, behavior and design of computers” Abd-Alla: “The design of the system specification at a general or subsystem level” Hennessy and Patterson: “The interface between the hardware and the lowest level software” :. the design of the computer at the hardware or software interface.

Structure and function Structure – The way in which the components relate to each other. E.g. connection between ALU and control unit, connection between Instruction register and instruction decoder. Function – The operation of each individual component as part of structure. E.g. How the ALU, Instruction register and instruction decoder work.

Function These are the basic functions that a computer can perform. -Data processing -Data storage -Data movement -Control

Cont.. Process data – data can be a variety of forms, and the range of processing requirements is broad. There are only a few fundamental methods of data processing ( refer ALU ). Store data – computer must temporarily store at least those pieces of data that are being worked on at any given moment at least a short-term data storage function (temporary register) and also long-term data storage function (store File). Move data – comp must be able to move data between itself and outside world. Device directly connected to computer is called peripheral. If data are moved over longer distances, the process is known data communication. Control – Control of three function above, and given by individuals who provides the computer with instruction.

Figure below depicts the four possible types of operations.

Structure There are four main components in a computer structure: -Central processing unit(CPU) – controls the operation of the computer and performs its data processing functions. -Main memory – stores data -I/O – moves data between the computer and its external environment -System interconnection – some mechanism that provides for communication among CPU, main memory and I/O. Traditionally a computer consist of single CPU, but in recent years, there has been increasing use of multiple processors in single computer.

The computer: Top-Level structure

The central processing unit Control unit – controls the operation of the CPU and hence the computer. ALU – perform data processing function Register – provides storage internal to CPU CPU interconnection – mechanism provides communication among the control unit, ALU and register.

14 Computer Structure Level one: The computer is device that can communicate with the outside world, and store and manipulate data. –The box, which can connect to networks (communication) and peripherals (I/O) –Software: operating system and applications

Computer Structure Level two: The computer has four component parts, –CPU (Central Processing Unit) –Main Memory (RAM: Random Access Memory) –I/O (Input/Output) –System Interconnection (buses)

Computer Structure Level three: The CPU has four components –Arithmetic Logic Unit (ALU) –Floating Point Unit (FPU) –Registers (Data, Instruction, Stack, Integer, Floating Point) –Control Unit –Internal CPU connections (wires)

Computer Structure Level four: The control unit has three internal components –Sequencing logic –Control unit registers and decoders –Control memory

Any Question !!!!!! OR Quiz !!!

Sketch the internal connection of a Simple CPU and explain in detail how it works What are the differences between single core technology and multi core technology. Give 10 advantages of 8 bit processor and 64 bit processor.