COMPUTER ARCHITECTURE

JC Harambearachchi

Recommended Text

1 Computer Organization and Architecture by William Stallings

2 Structured Computer OrganisationAndrew S. Tanenbaum

A Computer is

• A programmable machine. It can execute or run a pre-recorded list of instructions which follow certain rules (a program).

• Modern computers are electronic and digital. The actual machinery -- wires, transistors , and circuits -- is called hardware; the instructions and data are called software.

fig computer

• Input process output

Computer System

• Hardware• Software

– OS– Application SW

• Live ware

1 input operation2 processing operation-cpu3 storage operation-primary / secondry4 output operation5 Communication operations

What are basic operations of a Computer ?

Components of a Computer System

• Computer hardware provides the physical mechanisms to process, store, and input /output data. Includes CPU, memory, I/O devices

• Software provides instructions to tell the hardware what tasks to perform. It includes system (eg Windows XP) and application (eg Excel) software

Data in the computer may be representing numbers, characters, graphics etc but is always kept in a form that the hardware and software can manipulate.

• central processing unit• primary memory • secondary storage • input devices • output devices • communications devices• I/O cards• System Bus

What are the major Hardware components of the computer ?

• Keyboard pic• mouse

Input Hardware

• cpu pic• Memory chips pic

• Motherboard pic

Process and memory Hardware

• Hard drive• Floppy • Cd/dvd

Storage Hardware

• Monitor• Speaker• Printer

• Video card• Sound card

output Hardware

• Modems pic

Communication Hardware

• System Software– Windows pic– Linux pic

• Device drivers

• Application softwaere– Word – Exel– ppt

Software

• Entertainment• PERSONAL• Education• Productivty• Specality

– Word processing pic– Spread sheets– Database– Ppt– Quicken microsoft money

Application Software types

• Drawing• Web page desin• cad

Application Software types

Block Diagram of a Computer

Main Memory

IOD IOD IOD

IO Modules

CPU

Computer Hardware

1 Hardware- the CPU

• CPU performs actual processing of data, according to instructions from programs.

• Data and programs are stored in primary and secondary memory, and moved to and from CPU as required.

• Signals representing data and instructions travel between system components along electronic pathways, called buses. Capacity of bus is critical to system performance.

Central Processing Unit ( CPU)

1. Acting as the brain of the computer’

2. Currently the Intel-Pentium microprocessor is the most common CPU though there are many types

Hardware - The Processor• The CPU is a general purpose processor that performs data

manipulation and/or transformation functions including computations, comparisons and data movement.

• The CPU consists of 3 main parts:

– ALU - where arithmetic and logical operations performed

– Control Unit - controls data movement and execution of instructions

– Registers - small high speed storage areas

Components of a computer system

Computer Hardware

2 Hardware - memory

• Memory - Purpose of memory is data storage. Two major types of memory :

• Primary memory - to hold data and instructions during processing – eg RAM. Relatively limited capacity and volatile

• Secondary memory - to provide permanent long term

storage – eg hard disk. High capacity and non-volatile

Main Memory (RAM)

1. Different from disk storage2. used to temporarily store Data3. in modern computers memory is 512 MB.

Hardware- memory

• Digital computers deal with data in binary form - all data is represented using just two digits - 1 or 0. Letters and other symbols are assigned unique binary codes.

• Primary memory consists of a set of locations defined by sequentially numbered addresses. Each location contains a binary number that can be interpreted as data or an instruction.

0

1

2

3

4

5

1 0 0 1 0 0 0 1

1 1 0 1 0 0 1 1

0 1 0 0 0 0 0 0

1 0 1 0 0 1 1 1

1 1 1 0 1 0 1 0

1 1 0 0 1 0 1 0

Memory locations, using an 8 bit word

Memory locations are called words. Words are 8 bits (one byte) in size, or a multiple of 8. Common word sizes are 16, 32 and 64 bits.

Hardware - memory

• Memory is commonly measured in multiples of bits and bytes. 1 bit = 1 binary digit (0 or 1).

1. 1 byte = 8 bits

2. 1KB = 1024 bytes = 210

3. 1MB = 1024 KB= 220

4. 1GB = 1024 MB = 230

5. 1TB = 1024 GB = 240

Hardware - memory

• Secondary storage consists of non-volatile high-capacity devices to store programs and data not currently required by CPU.

• Hard and floppy disks, and tapes store data as magnetized spots.

• CD’s and DVD’s store data as pits or surface marks detectable by laser light.

3 Hardware – I/O

• Input Devices collect & translate raw data into form useable by computer. e.g keyboard accepts letters and numbers and converts them to a binary code such as Unicode.

• Output devices produce results in useable form for user (or another device). e.g. monitor converts binary codes to characters and images, whilst modem converts digital data to analog form for transmission over telephone lines.

Hardware – I/O Peripherals

1 Input Devices• Mouse• Keyboard

2 Output Devices• Monitor (VDU)• Printer

3 Secondary Storage Devices• Hard Disk• CD / DVD / Floppy

I/O Hardware

4 Hardware - I/O Modules

• Interface between System Bus and other Peripherals• example

– Sound cards – Video cards – Network cards– PCI cards

5 Hardware - System Bus

• series of electronic path ways and connecting other components of the computer.

Computer

Main Memory

InputOutput

SystemsInterconnection

Peripherals

Communicationlines

CentralProcessing Unit

Computer

Structure - Top Level

Structure - The CPU

Computer Arithmeticand Login Unit

ControlUnit

Internal CPUInterconnection

Registers

CPU

I/O

Memory

SystemBus

CPU

Types of computers

• Personal Computer– Microprocessor

• Mini computer• Main frame• Super computer

Types of computers• supercomputer : An extremely fast computer that can perform hundreds of

millions of instructions per second. – IBM ASCI pic

• mainframe : A powerful multi-user computer capable of supporting many hundreds or thousands of users simultaneously. – Banks air lines vp2400 pic

• Work stations minicomputer : A multi-user computer capable of supporting from 10 to hundreds of users simultaneously. – Designing , movies , Sun ws pic

• Microcomputers personal computer : A small, single-user computer based on a microprocessor. – Desktop PC pic– Notebook pc (laptop)– PDAs palmtops

• Microcontrollers embeded computers

• Server and client

What are Computer Ports ?

• Connection point

• examples1. Serial port (Com)2. Parallel Port3. USB port4. Ethernet Port

Basic concepts - communication

• Most modern computers no longer operate in isolation - they connect to other computers via modem or a network.

• To enable this communication, specialized hardware and software must be added to computers.

• In combination with other devices such as telephones, cabling, satellites, microwaves etc. , a communications network is created

1 Data processing2 Data storage3 Data movement4 Control

What are Major functions of a Computer ?

Functional view

DataMovementApparatus

ControlMechanism

DataStorageFacility

DataProcessingFacility

Operations (1)

• Data movement– e.g. keyboard to screen

DataMovementApparatus

ControlMechanism

DataStorageFacility

DataProcessingFacility

Operations (2)

• Storage – e.g. Internet download to disk

DataMovementApparatus

ControlMechanism

DataStorageFacility

DataProcessingFacility

Operation (3)

• Processing from/to storage – e.g. updating bank statement

DataMovementApparatus

ControlMechanism

DataStorageFacility

DataProcessingFacility

Operation (4)

• Processing from storage to I/O– e.g. printing a bank statement

DataMovementApparatus

ControlMechanism

DataStorageFacility

DataProcessingFacility