1 the hong kong polytechnic university department of electronic and information engineering eng224...

1

THE HONG KONG

POLYTECHNIC UNIVERSITYDepartment of Electronic and Information Engineering

ENG224ENG224

Information TechnologyInformation Technology

Part I: Computers and Internet Part I: Computers and Internet – – Dr Daniel Lun, EIEDr Daniel Lun, EIE

Part II: Data Processing Part II: Data Processing – – Mr. S.M. Lau, COMPMr. S.M. Lau, COMP

Part III: NetworkingPart III: Networking– – Dr Andy Leung, EIEDr Andy Leung, EIE

2

THE HONG KONG


ENG224ENG224

Information TechnologyInformation TechnologyPart-IPart-I

Computers and InternetComputers and Internet

Lecturer:Lecturer: Dr. Daniel Pak-Kong LUNDr. Daniel Pak-Kong LUN

Room:Room: DE637DE637 Tel:Tel: 27666255 27666255E-Mail:E-Mail: [email protected]@polyu.edu.hkWeb page:Web page: www.eie.polyu.edu.hk/~enpklun/www.eie.polyu.edu.hk/~enpklun/

ENG224/ENG224.htmlENG224/ENG224.html

3

THE HONG KONG


Contents

Introduction of Computers Operating System Case Study: Linux Internet Internet Programming - XHTML

4

Information Engineering

Information Technology

Information Systems

Electronic Engineering

Mechanical Engineering

Electrical Engineering

System Engineering

THE HONG KONG


5

An example – Mobile Banking

Information Systems– To study the various issues in running and

managing a mobile banking business

e.g. Risk management, Organizational behavior, Psychologies of mobile customers, etc.

Information Technology– To optimally integrate the required technologies to

enable a mobile banking business

e.g. Mobile Networking, Security control, Data processing for mobile transactions, etc.

THE HONG KONG


6

An example – Mobile Banking (Cont)

Information Engineering– To study the techniques required for the

implementation of a mobile banking business

e.g. Data transmission through mobile networks, Mobile handset design for data transmission, Data encryption algorithms, Database design and interface, etc.

THE HONG KONG


7

Requirements of an IT Practitioner

To understand the needs of the customers of different information systems and the organizations that provide those systems

To know clearly well the attributes, limitations, strengths and the integration methods of the technologies that enable those information systems

To understand the basic principles of the information engineering techniques for the implementation of those information systems

THE HONG KONG


8

Computer Networking

Data Processing

Three basic elements of IT

THE HONG KONG


9

ENG224

INFORMATION TECHNOLOGY – Part I1. Introduction to Computers

1. 1. Introduction to ComputersIntroduction to Computers

10

Reference

Peter Norton, Introduction to Computers, McGraw Hill, 5th Ed, 2003

ENG224


11

ENIAC • The first practical

computer• Built in 1945,

weighed more than 30 tons

• Require 1500 sq. feet

In 1949, Popular Mechanics magazine predicted “computers in the future may perhaps only weigh 1.5 tons !!!”

In 1949, Popular Mechanics magazine predicted “computers in the future may perhaps only weigh 1.5 tons !!!”

ENG224


12

Components of a computer system

ENG224


13

Hardware

ENG224


14

Hardware

CPU: Central Processing Unit– Brain of the computer– Manages all devices and performs the actual

processing of data– Carry out instructions given by user– For Personal Computer (PC), the CPU is usually

included in a single Integrated Circuit (IC) chip (called Microprocessor)

– Nowadays, one or more microprocessors (chips) can be used to form a CPU Parallel Processing

ENG224


15

Hardware

Input and Output devices– Interface between the outside world and the

computer system– Input devices: keyboard, mouse – Output devices: monitors, printers– Other I/O devices: network adapter, USB, disk

interface …

ENG224


16

Hardware Memory

– Internal memory / Main memoryRandom Access memory (RAM)

– Main feature 1: volatile requires continuous supply of electrical power to retain information

– Main feature 2: cheap in terms of bytes per dollar suitable for large volume data storage

– Functions: Receive commands / data from keyboard Store info ready to be sent to output Store currently running programs/their data Store immediate data generated by the currently running programs

ENG224


17

ENG224


Another kind of memoryRead Only Memory (ROM)

– Main feature 1: non-volatile data retain even when the power is off

– Main feature 2: relatively expensive and can only be written once suitable for storing essential data but in small volume

– Usually used for system boot up and basic control of I/O devices When a computer first powers up, nothing is in RAM Need ROM to store the instructions to set up various I/O devices, such as disk interface card, video adapter card, sound card, etc.

– ROM is used to store BIOS (Basic Input/Output Systems)

18

Hardware

Storage devices– External memory

Non-volatile Used to store programs/data for future use Also used when the capacity of the internal storage is

insufficient to keep the currently running programs and the data required

Floppy disks, hard disks, CD ROMs, Magnetic tapes

ENG224


19

Hardware

Main differences between storage & memory:– Larger capacity in storage than in memory– Data in storage are retained while data in memory

disappear when power is off– Storage is much cheaper than memory

ENG224


20

ENG224


Instructions / DataCPU

I DI I I

II I I

I I ID D

D D D D D D00 01 02 03 04 05 06 07 08 09

10 11 12 13 14 15 16 17 18 19

MemoryAddress

Control

I/OI: Instruction

D: Data

Buses – Linking up the CPU, Memory and I/O devices

2021

22I/O

I/OExternal Storage

21

ENG224


Stored Program Concept – In 1949, Dr John Von Neumann defined the stored

program concept that greatly affected the development of nowadays computers

– Suggested that program instructions should be stored in a memory unit just like data

Instructions: Commands of user Data: Information that commands work on

– Hence rather than hardware programmable, should be software programmable

22

Hardware - Instructions Most CPUs have built in a few hundreds of standard

operations– E.g. add, subtract, multiplication, division, AND, OR,

NOT, etc. Each operation is represented by an instruction code

– E.g. Add 1010100101– Subtract 1000100001– :

When an instruction code is fetched from memory to the CPU, the CPU knows that the corresponding operation should be performed

ENG224


23

Hardware - Instructions• A computer program is constructed by a combination of

different instruction codes

• Called as Machine Language Program, since it is written by 0 and 1, the only language that the CPU can understand

• 0110001111000010 ; the 1st instruction

0001000111100011 ; the 2nd instruction

:

:

0011000100001000 ; the n-1th instruction

1000001001010101 ; the nth instruction

MachineLanguageProgram

ENG224


24

Instructions / DataCPU

I DI I I

II I I

I I ID D

D D D D D D00 01 02 03 04 05 06 07 08 09

10 11 12 13 14 15 16 17 18 19

MemoryAddress

Control

II

ENG224


I/O I: Instruction

D: Data

Fetch and Execute – Every instruction should go through two phases of

processing: fetch & execute

2021

22

I

00

R

00

R

FETCH EXECUTE

CPU

01

R

01

R

FETCH

05

W

D

05W

DEXECUTE

02

R

02

R

FETCH

I/O20

W

20

D

D

W

EXECUTE

I/OI/O

25

• Fetch – Send address 01 to address bus– Send control signal Read– Get instruction I at address 00

• Execute – Send address 05 to address bus– Send data D to data bus– Send control signal Write

Example

ENG224


26

Software - Programming• Programming – the way to generate a program

• Computer can only understand 0 and 1

• The most direct way to communicate with the computer is to use 0 and 1 Machine Language Programming• 0110001111000010

0001000111100011

:

:

0011000100001000

1000001001010101

MachineLanguageProgram

Very tedious and can make error easilyVery tedious and can make error easily

ENG224


27

Software - Assembly Language Programming• Assembly Language is created to help human instructs CPU

to work

• By using a tool called Assembler, assembly language program can be converted into machine language program

Assembler

01100011110000100001000111100011

::

00110001000010001000001001010101

mov ax, #0add ax, $1234

::

mov bx, #22mov $2345, bx

Assembly Language Machine Language

ENG224


28

ENG224


• Different CPU will have different set of assembly language codes

• In fact, to understand an assembly language program, we need to first understand the architecture of the CPU

ALU: Arithmetic and Logic Unit : For doing arithmetic and logic operation)Registers: Some very fast memory inside the CPU chip

Memory

CPU

ALU

Registersaxbxcxdx

29

ENG224


Memory

CPU

ALU

Registersaxbxcxdx

A sample assembly language program

mov ax, #0 ; ax =0loop: add ax, $1234

; add the content at memory ; address 1234 to axmov bx, #22 ; bx = 22add ax, bx ; ax = ax + bxjmp loop; go to the instruction with ; label “loop”

30

Software - High Level LanguageProgramming• Assembly language programming is still too complicated for

general users

• They are far from human used language

e.g. “Set W equal to W plus X minus Y divided by Z”

“Repeat the next sequence of instructions until X is less than 0 or Y equals Z”

• A high level language is required to close the gap between human and computers

ENG224


31

main(){ cout << “Hello!”;}

Compiler

Linker10110101010101010101 :

High Level Program

ExecutableMachine Language Program

Object codeLibrary

ENG224


32

ENG224


Machine Language Programming– No application nowadays

Assembly Language Programming– Advantage: Less complicated than Machine Language. Usually

generate more efficient code than HLL– Disadvantage: Need the understanding of CPU structure. Still

difficult to program– Application: Sometimes use in the programming of embedded

systems (e.g. CPU of printer, washing machines, etc.)

High Level Language Programming (such as C/C++)– Advantage: Need the least amount of effort to write a program– Disadvantage: The program written may not be optimal

(depends on the compiler)– Application: For large scale programs

33

Banking System / Web Browser / Media player

Hardware & Software

Physical devices / Micro-architecture level

Operating System

GUI / Command interpreter

Application Software

System Software

Hardware

ENG224


34

ENG224


User interacts with application software System software enables the application software

to interact with computer CPU and help the computer to manage its internal resources (hardware)

35

Application Software

Develop to fulfill certain needs of users Either customized or packaged

– Customized software Designed for a particular customer according to their

needs Payroll, inventory control, …

– Packaged software Developed for general use Microsoft word, excel, Access, power-point, …

ENG224


36

System Software

Exists primarily for the computer itself Hides the hardware complexities Brings the different hardware configurations

into common platforms and accessible by the users

Consists of several programs, the most important one is the operating system (master control program that runs the computer)

ENG224


37

Operating System Master control program

– Manage all resources of the computer CPU, memory, disk, monitor, network, …

– Co-ordinate running programs Runs as soon as the computer boots

up, until the computer shuts down Usually store in the hard disk and load

into the memory when the computer starts

Need the help of BIOS for I/O devices E.g. Windows, Unix, Linux

ENG224


BIOS

Operating System

I/O DevicesOther resources

38

• When power up, nothing is in RAM. No control is possible to the hard disk to load the OS

• CPU starts to read the BIOS instructions stored in the ROM

• Things that normally perform– Initialize all I/O devices: hard disk, video, mouse,

keyboard, CD-ROM, etc– Load the bootstrap loader of the operating system

to RAM– Start to execute the bootstrap loader in RAM

• The bootstrap loader further loads the other part of the operating system to the RAM

ENG224


How the OS is loaded into memory?

39

CPU

Main Memory (RAM)

BIOS(Stored in

ROM)

Hard Disk

Mother Board

Disk Interface

Video Interface

Monitor

Disk Interface

Video Interface

Bootstrap loader

Bootstrap loader

OS

OS

ENG224


1 the hong kong polytechnic university department of electronic and information engineering eng224...

Documents