Lecture 1 Overview of Computers and Programming

8/3/2019 Lecture 1 Overview of Computers and Programming

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LECTURE 1 :

OVERVIEW OF

COMPUTERS ANDPROGRAMMING

KK10103/KK14303 Programming Principles

Prepared By Tan Soo Fun



Contents

1.1 Introduction

1.2 Electronic Computers Then and Now

1.3 Computers : Hardware

1.4 Computers : Software

1.5 The Software Development Method

1.6 Applying the Software Development Method

CASE STUDY : CONVERTING MILES TOKILOMETERS



Learning Outcomes

Upon completion of this topic, the studentsshould able to :- Describe basic computer systems concepts

Identify the basic elements of computer hardware andsoftware

List and describe the classifications of computerlanguages

Apply the software development method



1.1 Introduction

Source : http://www.freeinfosociety.com/article.php?id=74

Bill Gates

- Born on October 28, 1955in Seattle, Washington-Start Microsoft 1975

http://www.freeinfosociety.com/article.php?id=74

http://www.freeinfosociety.com/article.php?id=74



1.1 Introduction

Steven Paul "Steve" Jobs

- Born February 24,1955, San Francisco-Start Apple Inc. , 1976



1.1 Introduction

Robin Li李彦宏

- Born inYangquan, Shanxi, China-Start China's most popularsearch engine Baidu



1.1 Introduction

Mark

Zuckerberg - born May 14, 1984-co-founder of Facebook




Atanasoff –BerryComputer (ABC)First Electronic Computer, 1937 John Vincent Atanasoff ,Clifford Berry at Iowa StateUniversity The machine was notprogrammable, being designedonly to solve systems of linear

equations




ENIAC (Electronic NumericalIntegrator And Computer) first general-purposeelectronic computer

created at University ofPennsylvania, funded by UnitedStates Armydesigned tocalculate artillery firing tables forthe United States Army's Ballistic

Research Laboratory




Third Generation

IBM 7090

designed for "large-scalescientific and

technological applications

PDP-8- First successfulcommercial minicomputer - produced by Digital

Equipment Corporation(DEC) in the 1960s




Fourth Generation

VAX -an instruction set architecture (ISA)-developed by Digital Equipment

Corporation (DEC) in the mid-1970s




Intel Atom processor chip

contains the full circuitry of a central processing unit in an integrated circuitwhose small size and low power requirements make it suitable for use inmobile internet devices. (Intel Corporation Pressroom Photo Archives)




Now

(a) Notebook Computer (HP Pavilion

dv5©, Courtesy of Hewlett-Packard).

(b) Palmtop Computer (iPhone 4G©,

Courtesy of Apple, Inc.)

(c) Desktop Computer (iMac©, Courtesy

of Apple, Inc.)




Future ??



1.2 Electronic Computers Then and Now –



1.1 Electronic Computers Then

and Now-Future ??




Computers ?? a device that can perform computations and

make logical decisions billions of times faster thanhuman beings can.

Modern Computers can be categorized (sizeand Performance) into :

Personal ComputersMainframes

Supercomputers




Components of Computers




Components of Computers (Top Level View)




Memory

1000 Memory Cells inMain Memory




Bytes

The amount of storage required to store a singlecharacter

Bits The smallest element a computer can deal with

A binary digit, a 0 or a 1




Digits of the binary, octal, decimal andhexadecimal number system




Converting a binary number to decimalQuestion 1 : 110101 answer : 53

Conversion of decimal to binary

Will discuss more on tutorial 1



-The part of memory thatpermanently stores programs ordata

- Not Volatile Memory

-The part of main memory thattemporarily stores programs, dataand results

-Volatile Memory-Contents that disappearwhen the computer isswitched off


Main Memory

RAM

(Random AccessMemory)

ROM

(Read OnlyMemory)




Secondary Storage

Units such as disks or flash drives that retain data evenwhen the power to the drive is off

Why ?? Store more information/data that will fit in memory

Need permanent/semipermanent data –during power lossor when computer is turned off




File

Named collection of data storedon a disk

Directory

A list of the names of files storedon a disk

Subdirectory

A list of the names of files thatrelate to a particular topic







Central Processing Unit (CPU)

Controls the

operation of thecomputer

Performs thedata processing

functions

Referred to asProcessor




Computer Networks

Local Area Network (LAN)

Computers, printers, scanners and storage devices

connected by cable for intercommunication




Computer Networks

Wide Area Network (WAN)

A network such as the Internet that connects

computers and LANs over a large geographic area




Computer Networks

World Wide Web (WWW)

A part of the Internet whose graphical user interface

(GUI) make associated network resources easilynavigate

allows computer users to locate and view multimedia-based documents on almost any subject over theInternet—the Internet has exploded into the world’s

premier communication mechanism.

Today’s applications can be written to communicate

among the world’s computers.




Operating System

Software that controls interaction of user andcomputer hardware

manages allocation of computers resources







Bootstrap program is loaded at power-up orreboot

Typically stored in ROM or EPROM, generally

known as firmware Initializes all aspects of system

Loads operating system kernel and startsexecution




System Calls

Command-Line GUI

Interface



- Software used for a specific tasksuch as word processing,accounting , or database

management


Software

- manage and integrate acomputer's capabilities, but

typically do not directly applythem in the performance oftasks that benefit the use

Application

Software

System Software




Types of Software




Computer languages may be divided into threegeneral types:




Machine Language Binary number codes understood by a specific CPU

―natural language‖ of a computer and as such is defined byits hardware design

Advantages : Fast Processing and response Drawbacks : machine dependent (i.e., a particular machine

language can be used on only one type of computer).

Such languages are cumbersome for humans, asillustrated by the following section of an early machine-

language program that adds overtime pay to base pay andstores the result in gross pay: +1300042774

+1400593419+1200274027




Machine Language




Assembly LanguagesMnemonic codes that correspond to machine

language instructions Translator programs called assemblers were developed to

convert early assembly-language programs to machinelanguage at computer speeds.

The following section of an assembly-language programalso adds overtime pay to base pay and stores the result ingross pay:

load basepay

add overpaystore grosspay

Although such code is clearer to humans, it’sincomprehensible to computers until translated to machinelanguage.




Assembly Languages




High-Level Language

Machine-independent programming language thatcombines algebraic expressions and English symbols

Translator programs called compilers convert high-level language programs into machine language.

High-level languages allow programmers to writeinstructions that look almost like everyday English andcontain commonly used mathematical notations.

A payroll program written in a high-level languagemight contain a statement such as

grossPay = basePay + overTimePay;




High-Level Language




Entering, Translating,and Running a High-LevelLanguage Program

myprog.c

myprog.obj

myprog.exe







Flow of Information During Program Execution



1.5 The Software Development Method

Software development Method

1 6 A l i th S ft D l t



1.6 Applying the Software DevelopmentMethod

CASE STUDY : CONVERTING MILES TOKILOMETERS

PROBLEM :

Your summer surveying job requires you to studysome maps that give distances in kilometers and

some that use miles. You and your coworkers prefer todeal in metric measurements. Write a program thatperforms the necessary conversion

1 6 A l i th S ft D l t




Step 1 : Identify the system Requirements

PROBLEM :

Your summer surveying job requires you to studysome maps that give distances in kilometers andsome that use miles. You and your coworkers prefer to

deal in metric measurements. Write a program thatperforms the necessary conversion

1 6 Applying the Software Development




Step 2 : Analysis

Problem Input :

distance in miles

Problem Output : distance in kilometers

Relevant Formula

1 mile = 1.609 kilometers





Step 3 :Design

1. Get the distance in miles

2. Convert the distance to kilometers

3. Display the distance in kilometers

1 miles =1.609

kilometers





Implementation



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Lecture 1 Overview of Computers and Programming