CIT100 Introduction to CIT100 Introduction to ComputersComputers

Lecture 1Lecture 1

Computer ConceptsComputer Concepts

Overview of Operating SystemsOverview of Operating Systems

TopicsTopics

Basic computer conceptsBasic computer concepts Overview of Operating SystemsOverview of Operating Systems Evolution of Microsoft WindowsEvolution of Microsoft Windows

Basic Computer ConceptsBasic Computer Concepts

What is a Computer System?What is a Computer System?

By definition a computer pertains By definition a computer pertains only to the hardware. However in only to the hardware. However in order for the hardware to work it order for the hardware to work it software is required. Therefore a software is required. Therefore a computer system consists of the computer system consists of the hardware or physical components hardware or physical components and software, an operating system.and software, an operating system.

Memory

Central processing unit(CPU)

Input

Auxiliary Storage

Auxiliary StorageAuxiliary

Storage

Output

Any ComputerAny Computer

The first Business PC: The IBM PCThe first Business PC: The IBM PC

A combined effort between A combined effort between IBMIBM (credibility and (credibility and marketing), marketing), MicrosoftMicrosoft (operating system), and (operating system), and IntelIntel (microprocessor); introduced in 1981 (microprocessor); introduced in 1981

IBM was a mainframe company; it was hounded IBM was a mainframe company; it was hounded by antitrust legislation, and did not believe in the by antitrust legislation, and did not believe in the future of the PC (initial forecast was 250,000 future of the PC (initial forecast was 250,000 units)units)

The PC was created as an ‘open’ machine The PC was created as an ‘open’ machine enabling independent contractors to develop enabling independent contractors to develop hardware and/or software to improve ithardware and/or software to improve it

PC clones quickly followed and the market soon PC clones quickly followed and the market soon exploded; IBM has a fraction of the market it exploded; IBM has a fraction of the market it createdcreated

IBM PC IBM PC

Approximately $4000 as shown.

The PC TodayThe PC Today

Inside the PCInside the PC

On

Off

All computers are based on the All computers are based on the binary number system binary number system

A A bitbit or binary digit has one of or binary digit has one of two values, zero or onetwo values, zero or one

A A bytebyte is the smallest is the smallest addressable unit of memory (8 addressable unit of memory (8 bits)bits)

ASCII ASCII provides for 256provides for 256(or 2(or 288) characters) characters• 01000001 – A01000001 – A• 01000010 – B01000010 – B• etc. etc.

httphttp://www.ascii-table.com://www.ascii-table.com//

Overview of OSOverview of OS

What is an Operating System?What is an Operating System?

It is a systems level programIt is a systems level program It interacts with the hardwareIt interacts with the hardware It interacts with the applicationsIt interacts with the applications It coordinates the activities that take place It coordinates the activities that take place

within a computerwithin a computer It provides External servicesIt provides External services It provides Internal servicesIt provides Internal services DesktopDesktop NetworkNetwork

External ServicesExternal Services

Services controlled by a userServices controlled by a user Start programsStart programs Manage stored dataManage stored data Maintain security (network systems)Maintain security (network systems) Access to utilities built-in to the OSAccess to utilities built-in to the OS

Internal ServicesInternal Services

““Behind the scenes”Behind the scenes” Input and OutputInput and Output

• Keyboard, Mouse, Printing, etc.Keyboard, Mouse, Printing, etc. Allocates system resourcesAllocates system resources

• Memory (Conventional, Expanded and Memory (Conventional, Expanded and Extended)Extended)

Manage the storage space for programs Manage the storage space for programs and dataand data• Keep track of where programs and data are Keep track of where programs and data are

stored on the storage devicesstored on the storage devices Detects equipment failuresDetects equipment failures

Network OSNetwork OS

Microsoft, Novell, UNIXMicrosoft, Novell, UNIX Provides file and print sharing servicesProvides file and print sharing services Provides user-level security of resourcesProvides user-level security of resources Requires high-end system called a file Requires high-end system called a file

serverserver Requires in-depth trainingRequires in-depth training Expensive to implementExpensive to implement

Desktop OSDesktop OS

Microsoft is main publisherMicrosoft is main publisher Single-userSingle-user Current versions have network capabilitiesCurrent versions have network capabilities GUI and Non-GUI versionsGUI and Non-GUI versions Required to use a computerRequired to use a computer

Non-Microsoft OSNon-Microsoft OS OS/2 – IBM competitor to WindowsOS/2 – IBM competitor to Windows

• No longer publishedNo longer published UNIXUNIX

• Developed by Bell LabsDeveloped by Bell Labs• Command drivenCommand driven

LinuxLinux• Unix-likeUnix-like• Several “flavors”Several “flavors”

Mac OSMac OS• Major Competitor to Windows-basedMajor Competitor to Windows-based• History of Mac OS at: History of Mac OS at: http://http://

www.guidebookgallery.org/guis/macoswww.guidebookgallery.org/guis/macos

Pre-Windows OSPre-Windows OS

DOS – Disk operating SystemDOS – Disk operating System• Command interfaceCommand interface• Non-GUI basedNon-GUI based• Single task orientedSingle task oriented• MS-DOS and PC-DOSMS-DOS and PC-DOS

MS-DOS for compatiblesMS-DOS for compatibles PC-DOS for IBM nameplatePC-DOS for IBM nameplate

• Official versions from 1.0 – 6.22Official versions from 1.0 – 6.22

DOS ScreenDOS Screen

WindowsWindows

Windows 1.0 - PresentWindows 1.0 - Present

Windows 1.0 first versionWindows 1.0 first version Introduced a Graphical User Interface (GUI) for Introduced a Graphical User Interface (GUI) for

PCsPCs Introduced Multitasking capabilities starting with Introduced Multitasking capabilities starting with

Windows 3.1Windows 3.1 Designed to compete with the MacDesigned to compete with the Mac Made the use of PCs more popular and easier to Made the use of PCs more popular and easier to

useuse Placed more demands on hardwarePlaced more demands on hardware Most popular interface in use todayMost popular interface in use today

Timeline of WindowsTimeline of Windows

Windows 1.0Windows 1.0 19851985 Windows 2.0Windows 2.0 19871987 Windows 3.0Windows 3.0 19901990 Windows 3.1Windows 3.1 19921992 Windows 3.11 WorkgroupsWindows 3.11 Workgroups 19941994

• Incorporates network featuresIncorporates network features

Timeline of WindowsTimeline of Windows

Windows NT 3.1Windows NT 3.1 19931993• Server Version OnlyServer Version Only

Windows NT 3.5Windows NT 3.5 19941994• Server Version OnlyServer Version Only

Windows NT 3.51Windows NT 3.51 19951995• Server Version OnlyServer Version Only

Windows NT 4.0Windows NT 4.0 19961996• Server and WorkstationServer and Workstation

Timeline of WindowsTimeline of Windows Windows 95Windows 95 19951995

• WorkstationWorkstation Windows 98Windows 98 19981998

• WorkstationWorkstation Windows 2000Windows 2000 20002000

• Server and WorkstationServer and Workstation Windows MEWindows ME 20002000

• WorkstationWorkstation Windows XPWindows XP 2001 2001

• WorkstationWorkstation Windows Vista (Longhorn)Windows Vista (Longhorn) 20072007

Windows 1.0Windows 1.0

Windows 2.0Windows 2.0

Windows 3.xWindows 3.x

Windows 95Windows 95

Windows 98Windows 98

Windows NT4Windows NT4

Windows 2000Windows 2000

Windows MEWindows ME

Windows XPWindows XP

Windows “Longhorn” (Vista)Windows “Longhorn” (Vista)

End of PresentationEnd of Presentation