Computer Organisation and Architecture · Some De nitions - Architecture Baer: The design of the integrated system which provides a useful tool to the programmer Hayes: The study

Computer Organisation and Architecture

Lecture 2

University of Ghana

Department of Computer Science

[email protected]

September 18, 2014

Lecture 2 (CSCD) Organization/Architecture - CSCD211 September 18, 2014 1 / 14

Architecture/Organization

Architecture - attributes visible to the programmer; They have directimpact on the logical execution of a program. Eg of these attributesinclude

-Instruction set-Number of bits-I/O mechanisms-Addressing techniques

Organization is how features are implemented - Refers to theOperational unit and their interconnections. Eg of organizationalattribute includes;

-Control signals-Interfaces-Memory technology


Some Definitions - Architecture

Baer: The design of the integrated system which provides a usefultool to the programmer

Hayes: The study of the structure,behavior and design of computers

Abd-Alla: The design of the system specification at a general orsubsystem level

Stallings: Computer ”architecture” refers to the set of attributes of acomputer system that are visible to a programmer

The key words that runs through these definitions are;-Design-Structure-Attributes


Structure and Functions

Structure: This is the way in which components relate to each other

Function refers to the operation of individual components as part ofthe structure

All computer functions/operations are grouped as;

-Data Processing-Data Storage-Data Movement-Control


Functional View

This depicts the four possibletypes of operations that can beperformed.


Data Movement

The computer can function as adata movement device. Movesdata from one device to theother. Computer must be able tocommunicate with outside world.Data must be accessible todevices outside computer. Thereare two types;-Peripheral-Data Communications


Data Storage

It can also function as a storagedevice. Thus data moves fromthe source/destination tocomputer storage and vice-versa.For long terms, data can bestored by Logging and Datarecords-For short terms, temporaryvariables such as buffers andprogram control data are used.


Data Processing from/to Storage

It can also function as a dataprocessing device from/tostorage. The basic function ofany computer is to processdata.Although end result may becomplex, there are few distincttypes of data processing.


Processing from storage to I/O

It can also function as a dataprocessing device from storage tothe operating environment(source/destination).


Design and Performance

The exact form of a computer system depends on the constraints andgoal for which it was optimized.

There are trade offs in relations to standards, cost, memory capacity,and latency.

Building blocks of the computer system still follows the IAS (instituteof Advance Studies) computer 60 years ago.

An increase in a machines performance can be viewed in one of two

-Reduced response time to an individual job-Increased in overall throughput


Performance cont...

There is also a trade off between price or cost and performance.

-price drops every year-performance increases almost yearly-memory size goes up a factor of 4 every 3 years or so

A computers performance can also be describe using the clock speed.this is sometimes misleading in that a computer with a higher clockrate may not necessarily have higher performance.

We can measure performance also by using the amount of cache aprocessor has. The higher the speed the greater the cache and thefaster the processor.


Performance Balance

With the increased in processor power against speed, other criticalcomponents of the computer have not kept up.

There is the need for performance balance in terms of organizationand architecture.

First, there is the need for processor increase. While processor speedhas grown rapidly, the speed with which data can be transferredbetween main memory and the processor has lagged badly.

Failure in the processors insistant demands results in the processorstalling in a wait state, and valuable processing time is lost.


Performance Balance cont...

Secondly, there is the need for memory capacity increase.

Thirdly, Memory speed lags behind processor speed.

Peripherals with intensive I/O demands : Another area of designfocus is the handling of I/O devices.

While the current generation of processors can handle the datapumped out by these devices, there remains the problem of gettingthat data moved between processor and peripheral.


ASSIGNMENT 1A

Since the development of the first computer, thus, IAS computersbased on John von Neumann architecture, there has been abottleneck problem between the processor and memory in relation todesign goals and performance. Identify the problem and give solutionsto how to solve the problem?

Deadline : Monday, 21st September 2014, 5pm

Format : pdf, maximum of one page

Send Solution to [email protected]


Documents

Computer Organisation and Architecture · Some De nitions - Architecture Baer: The design of the integrated system which provides a useful tool to the programmer Hayes: The study