Computer and Computer and Information ScienceInformation Science

Computer Computer Software and NetworkingSoftware and Networking Computer Computer Software and NetworkingSoftware and NetworkingChapter 1.2Chapter 1.2

AgendaAgendaAgendaAgenda Application SoftwareApplication Software Operating SystemsOperating Systems

SoftwareSoftwareSoftwareSoftware SoftwareSoftware is the is the programsprograms and and datadata that that

a computer uses.a computer uses. Programs are lists of instructions for Programs are lists of instructions for

the processor.the processor. Data can be any information that a Data can be any information that a

program needs: character data, program needs: character data, numerical data, image data, audio numerical data, image data, audio data, and countless other types.data, and countless other types.– Digitizing :Digitizing :The process of taking a visual image, or

audio recording and converting it to a binary form for the computer.

Types of ProgramsTypes of ProgramsTypes of ProgramsTypes of Programs Imagine that you have just turned Imagine that you have just turned

on your computer and have not yet on your computer and have not yet started any application. Are any started any application. Are any programs running? programs running?

Two types of softwareTwo types of software– Application softwareApplication software– System software/Operating systemsSystem software/Operating systems

Why do we need an OS?Why do we need an OS? What are the goals of an Operating

System?– The primary goal of an Operating System is

to make the computer system convenient to use.

– The secondary goal is to make the computer system efficient to use.

An Operating SystemAn Operating System It underlies all other software. It acts as an interface between a user of a acts as an interface between a user of a

computer and the computer hardwarecomputer and the computer hardware ItIt manages and coordinates computer manages and coordinates computer

system resources ( CPU, memory, file system resources ( CPU, memory, file system, I/O devices)system, I/O devices)

It provides the user Interface that is:– How can something as simple-minded as a processor and

memory present you with something as rich as the Mac or Windows GUI?

Operating system services ...

Control basic input and output

Allocate system resources

Manage storage space

Operating Systems

Detect equipment failure

Maintain security

Operating system services ...

• You ask MS Word to OPEN a document– File menu/Open…

– WHAT WILL YOU SEE?

– What really just happened in the box?

WORD called on WORD called on O.S.O.S. to present to present you with that file list!you with that file list!O.S. must look at:O.S. must look at:1.1. Disk Directory (list of Disk Directory (list of filenamesfilenames))2.2. File Allocation Table (File Allocation Table (FATFAT)…. )….

(list of file (list of file locations: starting locations: starting position/cluster number on the disk)position/cluster number on the disk)

System calls

Multi-taskingMulti-tasking >1 program or person can share

computer resources. – CPU is idle ~90% of time, waiting for user input !

– One program active; Others running in the background

OS must protect each program’s memory area to ensure that instructions and data don’t “leak” into an area allocated to another program. If it fails, programs can crash…more shortly!

Booting and BIOSBooting and BIOSBooting and BIOSBooting and BIOS When a computer is started up, the When a computer is started up, the

hardware will automatically load the hardware will automatically load the operating system and start it running. This operating system and start it running. This process is called process is called bootingbooting..

BIOS is the boot program on a computer, BIOS is the boot program on a computer, and controls the computer from the time and controls the computer from the time you start it up until the operating system you start it up until the operating system takes over. When you turn on a PC, the takes over. When you turn on a PC, the BIOS first conducts a basic hardware BIOS first conducts a basic hardware check, called a Power-On Self Test (POST), check, called a Power-On Self Test (POST), to determine whether all of input/output to determine whether all of input/output devices are present and working. Then it devices are present and working. Then it loads the operating system into your loads the operating system into your computer's RAM.computer's RAM.

ROM (Read-only-Memory)ROM (Read-only-Memory)ROM (Read-only-Memory)ROM (Read-only-Memory) ROM refers to computer memory ROM refers to computer memory

chips containing permanent or chips containing permanent or semi-permanent data. Unlike RAM, semi-permanent data. Unlike RAM, ROM is non-volatile; even after you ROM is non-volatile; even after you turn off your computer, the turn off your computer, the contents of ROM will remain . contents of ROM will remain .

BIOS is stored in a ROM. BIOS is stored in a ROM.

Various Operating SystemsVarious Operating Systems Windows : Developed by Microsoft

XP, Vista, windows7 Unix: Developed by AT&T for large

companies Linux: Open Source version of

Unix Mac OS: only for Mac hardware

e.g. Snow Leopard

UNIX

SunOS UNIX

login: smithPassword:Last login: Oct 15 17:42:09 from tserv1.edu

SunOS Release 4.1.1 #1: Wed Mar 20 11:24:14 AST 1991

You have mail.

% _

UNIX features a command line interface. Designed for minicomputers but is now also available for micros and mainframes.

UNIX features a command line interface. Designed for minicomputers but is now also available for micros and mainframes.

The UNIX prompt

Microcomputer Operating Systems

Why is it important for me to know which operating system is on my computer?

IMPORTANT !

WHAT HAPPENS when you SHUT DOWN improperly? Why should you care?

““Shutting down incorrectly is a little like Shutting down incorrectly is a little like stopping your car by driving it into a wall. stopping your car by driving it into a wall. It works, but it can cause some damage.”It works, but it can cause some damage.”

Computer terms bingoComputer terms bingoComputer terms bingoComputer terms bingo Follow the link Follow the link http://www.wcu.edu/ceap/Kirk/Merlot_Resources/KnowYourComputerTerms.swf

NetworksNetworksNetworksNetworks Computer Network: series of Computer Network: series of

computers linked together to share computers linked together to share data, hardware, and softwaredata, hardware, and software

Local Area Network (LAN) : series Local Area Network (LAN) : series of computers networked together of computers networked together over a relatively limited areaover a relatively limited area– campus– building

Stand-alone computer Stand-alone computer —— a computer not a computer not connected to a network.connected to a network.

WorkstationWorkstation —— name for a computer when it name for a computer when it is connected to a network.is connected to a network.

Local resources Local resources —— workstationworkstation’’s typical s typical resources: hard drive, software, data, and resources: hard drive, software, data, and printer.printer.

Network resources Network resources —— additional resources additional resources you have access to when connected to a you have access to when connected to a network: application software, storage network: application software, storage space for data files, and shared printers.space for data files, and shared printers.

Key Network TermsKey Network TermsKey Network TermsKey Network Terms

Network server Network server —— a computer connected a computer connected to the network that distributes to the network that distributes resources to network users.resources to network users.

Network printer Network printer —— a shared printer that a shared printer that provides output capabilities to all provides output capabilities to all network users.network users.

NodeNode —— a device on a network, including a device on a network, including workstations, servers, and printers.workstations, servers, and printers.

Identifies you as a user on the Identifies you as a user on the networknetwork

Logically connects a workstation to Logically connects a workstation to network drives and other resourcesnetwork drives and other resources

Requires a user to enter a Requires a user to enter a user ID user ID and and passwordpassword

The login process ...The login process ...The login process ...The login process ...

User account User account —— provides access to provides access to network resources.network resources.

Network administratorNetwork administrator or or supervisorsupervisor —— person responsible for setting person responsible for setting up user accounts and maintaining up user accounts and maintaining the network.the network.

Mapping Mapping —— assigning drive letters to assigning drive letters to network server disk drives.network server disk drives.

What drives are available??What drives are available??What drives are available??What drives are available??

View a directory or access files on network server drive F just as you would drives A and C.

Your workstation floppy drive A

Network server drive F

Your workstation hard disk drive C

Network printer

Using Programs on the NetworkUsing Programs on the NetworkUsing Programs on the NetworkUsing Programs on the Network

Step #1

Step #2

Step #3

Disk storage spaceDisk storage space Time and effort in updating Time and effort in updating

softwaresoftware Licensing costsLicensing costs

Sharing a program — with proper licensing many network users can access a program at the same time and save...

Parallel port

Workstation

Network printer

Using a Network PrinterUsing a Network PrinterUsing a Network PrinterUsing a Network Printer

The login process usually assigns a network printer to your workstation.

Output is redirected (captured) from the parallel port to the network printer.

Two documents are sentto a network printer at the same time . . .

Print Queue:1. Ceo.Doc2. Gnp.Doc

Ceo.doc arrives first

Gnp.doc arrives before printer completes Ceo.doc

Print queue Print queue —— special holding area special holding area on the network server where files are on the network server where files are stored until they are printed.stored until they are printed.

Network interface card (NIC) Network interface card (NIC) —— small circuit board that plugs into small circuit board that plugs into expansion slot.expansion slot.

– Key component for connecting your computer to a local area network– Sends data from a workstation over the network– Collects incoming data intended for your workstation

Network HardwareNetwork HardwareNetwork HardwareNetwork Hardware

Desktop network interface card (NIC)

Connecting NetworksConnecting NetworksConnecting NetworksConnecting Networks

Similar to Similar to telephone cabletelephone cable Has a plastic RJ-Has a plastic RJ-45 connector on 45 connector on either endeither end

Twisted pair cable (UTP) —

Wireless networks Wireless networks use radio or use radio or infrared signals to transmit data from infrared signals to transmit data from one network device to another.one network device to another.The network interface card contains The network interface card contains the transmitting devices.the transmitting devices.

Other Network ConnectorsOther Network ConnectorsOther Network ConnectorsOther Network Connectors

Provide mobilityProvide mobility Are used in environments where Are used in environments where

wiring is hard to installwiring is hard to install Can be good for temporary Can be good for temporary

installationsinstallations

Wireless networks:Wireless networks:Wireless networks:Wireless networks:

Software for NetworksSoftware for NetworksSoftware for NetworksSoftware for Networks

A network requires some special A network requires some special network software network software in addition to in addition to much of the same application much of the same application software typical of standalone software typical of standalone computers.computers.

Network license:Network license:Network license:Network license: Permits specified number of people Permits specified number of people

to use software on a networkto use software on a network Costs more than one single-user Costs more than one single-user

license but less than individual license but less than individual licenses for all network userslicenses for all network users

Available for most software Available for most software packages by contacting the packages by contacting the publisherpublisher

E-mailE-mailE-mailE-mail

Electronic mail (e-mail) Electronic mail (e-mail) is is correspondence conducted correspondence conducted between users on a computer between users on a computer network. network.

E-mail messages are E-mail messages are storedstored on a on a serverserver

When you read your mail, the When you read your mail, the server server forwardsforwards it to your it to your workstationworkstation

Store and forward Store and forward technology:technology:Store and forward Store and forward technology:technology:

Mail server

Your workstation

1. E-mail addressed to you is sent to the mail server

2. Mail stays on the mail server until you log on to your mail client.

3. Server forwards your mail to your workstation when you’re ready to read it.

VOIPVOIPVOIPVOIP

VoIP allows you to make telephone calls using the Internet.

Voice communication among the computers, free of charge

Calls to phone numbers for a fee

Streaming MediaStreaming MediaStreaming MediaStreaming Media Streaming media technology enables

you to include audio, video and other multimedia files into your web site.

Downloading vs StreamingDownloading vs StreamingDownloading vs StreamingDownloading vs Streaming Downloading :The user

downloads the file from the web server to her local hard disk, and then plays back the content using a player.

Streaming: The media Server sends data over the network only at the speed that is necessary for the client to render it properly and allows live content delivery.

More Internet ApplicationsMore Internet ApplicationsMore Internet ApplicationsMore Internet Applications FTP is a standard 

network protocol used to exchange and manipulate files over the Internet..

Instant Messaging, originally a Instant Messaging, originally a real-time communication via the real-time communication via the Internet using typed text and now Internet using typed text and now includes voice and videoincludes voice and video