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Chapter 5 provides knowledge of internet hardware, software and communications. This chapter includes contents: Structure of the internet, servers, communications media, storage area networks (SANs), digital subscriber lines (DSL), broadband, integrated services digital network (ISDN),...
Chapter 5, Internet Hardware, Software and Communications Outline 5.1 Introduction 5.2 Structure of the Internet 5.3 Hardware 5.3.1 Servers 5.3.2 Communications Media 5.3.3 Storage Area Networks (SANs) 5.4 Connecting to the Internet 5.4.1 Digital Subscriber Lines (DSL) 5.4.2 Broadband 5.4.3 Integrated Services Digital Network (ISDN) 5.4.4 T1 and T3 Lines 5.5 Internet2 5.6 Software 5.6.1 Application Service Providers (ASPs) 5.6.2 Databases 2001 Prentice Hall, Inc. All rights reserved Chapter 5, Internet Hardware, Software and Communications Outline 5.7 Operating Systems 5.7.1 UNIX 5.7.2 Microsoft Windows 5.7.3 Linux 5.7.4 Mac OS X 5.8 Enhancing Business Communication 5.8.1 Intranets and Extranets 5.8.2 Streaming Audio and Video 5.8.3 Internet Telephony 5.8.4 Web Casting and Webconferencing 2001 Prentice Hall, Inc. All rights reserved 5.1 Introduction • • • • • Connection media Cost of connecting Streaming media (audio and video) Internet telephony Technologies used to enhance online business communications 2001 Prentice Hall, Inc. All rights reserved 5.2 Structure of the Internet • IP address (Internet Protocol) – Computers use IP addresses to locate other computers on the Internet • Packet – Source address, a destination address, sequencing information, errorcontrol information and the data to be delivered to the destination address • Router – Used to move packets across the Internet efficiently 2001 Prentice Hall, Inc. All rights reserved 5.3 Hardware • The Internet employs many advanced hardware technologies – Various communications media used to connect hosts – The roles hosts play on the Internet • Servers • Communications Media • Storage Area Networks (SAN) 2001 Prentice Hall, Inc. All rights reserved 5.3.1 Servers • Server – A host on the Internet that manages network resources and fulfills requests from clients – Web servers, email servers, database servers and file servers – A single server may provide multiple services • A Web server stores Web pages and delivers the pages to clients upon request • Protocols for delivering information over the Web – – – – Hypertext transfer protocol (HTTP) File transfer protocol (FTP) Post office protocol (POP) Simple mail transfer protocol (SMTP) 2001 Prentice Hall, Inc. All rights reserved 5.3.2 Communications Media • Communications medium – The hardware that connects computers and other digital equipment • Bandwidth – Indicates how much data can be transferred through the medium in a fixed amount of time – Usually measured in bits per second (bps) • Copper wire – The primary communications medium 2001 Prentice Hall, Inc. All rights reserved 5.3.2 Communications Media • Fiberoptic cable – Composed of flexible glass fiber, is thinner and lighter than traditional copper wire, yet has much wider bandwidth – Uses short bursts of light to represent bits • Optical modem – Modem stands for modulator and demodulator – Translates digital signals from computers into light through a process called modulation • Opto chip – Converts the most basic particle of light, the photon, into an electric current – Allows tremendous amounts of data to be sent over fiber optic networks through particles 100 times smaller than the diameter of a human hair 2001 Prentice Hall, Inc. All rights reserved 5.3.2 Communications Media • The strength of a signal transmitted over a communications medium is reduced as the signal travels farther and farther • Repeater – Can be used to alleviate this problem by amplifying and retransmitting the signal across segments of copper wire or fiberoptic cable • Transmission costs – Fiberoptic cable is more expensive than copper wire – Installation of fiberoptic cable is more complicated than installation of copper wire – Fiberoptic cable requires fewer repeaters 2001 Prentice Hall, Inc. All rights reserved 5.3.3 Storage Area Networks • Companies produce large volumes of data to support sales analysis tools, enterprise resource planning (ERP) systems, multimedia Web sites and ecommerce systems • Storage Area Network (SAN) – Provides highcapacity, reliable data storage and delivery on a network – Allows network administrators to collect data in logical groups on data servers distributed throughout the network – SAN devices store large volumes of data and may also provide backup and recovery services 2001 Prentice Hall, Inc. All rights reserved 5.7 Operating Systems • Operating system (OS) – Software that manages the resources on a computer – Multiuser OS • Allows more than one user to run programs simultaneously – Multiprocessor OS • Controls a computer that has many hardware CPUs – Multitasking OS • Allows multiple applications to run simultaneously – Multithreading OS • Allows an individual program to specify that several activities should be performed in parallel • Major operating systems used in desktop computers are UNIX , Linux , Macintosh and Windows 2001 Prentice Hall, Inc. All rights reserved 5.7.1 Unix • Multics – “All things to all people” – Bell Laboratories, General Electric and Project MAC • Unix – Developed by Bell Laboratories after leaving the Multics project – First version written in assembly language – Unique design and coherence – Met the needs of programmers who were building software and of administrators who control software development efforts 2001 Prentice Hall, Inc. All rights reserved 5.7.1 Unix • University of California at Berkley – From time sharing to systems appropriate for studying distributed computing environments • Sun Microsystems – Sun OS – Include facilities for supporting a graphics, windowbased, mouseoriented interface – Provided facilities for diskless workstations to use the network for file storing, sharing and paging • The Open Group – Controls the specification for UNIX and holds the trademark – www.unix-systems.org 2001 Prentice Hall, Inc. All rights reserved 5.7.2 Microsoft Windows • The most popular operating system in the world • Introduced in 1984 with graphical user interface (GUI) added to the DOS system • Windows 2.0 – Failed to make a large impact in the market – Took too long to open applications, change screens, etc. • Windows 3.0 – Achieved widespread success • Windows 95 – Introduced a new graphical user interface and increased performance • Windows 98, Windows NT and Windows 2000 2001 Prentice Hall, Inc. All rights reserved 5.7.3 Linux • Linux – A UNIXlike operating system that has been developed by volunteers worldwide – Initially developed by Linus Torvalds – Greatest success on the serverside • Version 1.0 – Released in 1994, gained market share to become one of the world’s most widely used operating systems • The Gnome Foundation – Founded to develop a free Linuxbased desktop environment and a free application framework to compete with Microsoft Office for the desktopcomputer environment 2001 Prentice Hall, Inc. All rights reserved 5.7.3 Linux • Open source software – Freely available source code, so that anyone can use, customize and make updates to the software • Kernel – The core of the operating system • Most of the applications that run on Linux are freely available over the Internet and on many CDROM distributions • GNU General Public License (GPL) – One of the most widely used opensource licenses – Requires that the source code for GPLlicensed software, as well as the source code for any modifications or improvements to that software, is made freely available to the public 2001 Prentice Hall, Inc. All rights reserved Microsoft.NET • Microsoft.NET – Weaves together the operating system, the Internet and each device to create applications and services to be accessed anytime, anywhere, from any device – Could potentially support UNIX and Linux • Building and maintaining .NET components – – – – Windows.NET Visual Studio.NET Integrated development environment (IDE) NET Enterprise Servers and the .NET framework • .NET applications will be built with XML 2001 Prentice Hall, Inc. All rights reserved 5.7.4 Mac OSX • Achieved great success in the 1980s, dominating the market for GUIbased personal computers • One of the first widely available systems to use a windowbased (i.e., a GUI) interface, a mouse and icons • Release of Windows challenged MacIntosh sales • Mac OS X operating system – Core was built using industry open standards based on Unix • Aqua – New Mac OS X interface 2001 Prentice Hall, Inc. All rights reserved Internet Appliances • Internet appliances – Desktop devices designed specifically for connecting to the Internet – iPAQ Home Internet Appliance – Netpliance iopener • Devices allow you to browser the Web, send and receive email and access streaming media online • Limited functionality 2001 Prentice Hall, Inc. All rights reserved 5.8 Enhancing Business Communication • • • • Intranets Extranets Streaming audio and video Internet telephony – Makes PCtoPC and PCtophone calls possible, dramatically reducing the cost of communication • Web casting • Virtual conferencing • Wireless technology 2001 Prentice Hall, Inc. All rights reserved 5.8.1 Intranets and Extranets • Intranet – An organization’s internal network that uses the TCP/IP protocols of the Internet – Only authorized parties, such as the organization's employees, have access to an organization’s intranet – Used to store internal information • Extranet – An intranet that is also accessible by authorized external parties who are not members or employees of the organization – Members or employees might have unrestricted access to information on the extranet, whereas customers or vendors might have access to a limited subset of that information 2001 Prentice Hall, Inc. All rights reserved 5.8.2 Streaming Audio and Video • Streaming technologies – Allow users to send and process audio and video data continuously – Allows users to start playing the audio or video file while it is still downloading – Users can play music over the Internet – Users can watch a small video on a Web site 2001 Prentice Hall, Inc. All rights reserved 5.8.2 Streaming Audio and Video RealPlayer dialog. (Copyright© 19952000 Realnetworks, Inc. All Rights Reserved. RealNetworks, Real.com, RealPlayer are trademarks registered trademarks of of RealNetworks, Inc.) 2001 Prentice Hall, Inc. All rights reserved 5.8.3 Internet Telephony • Internet telephony – Enables communication over the Internet, allowing you to use your PC as a telephone – Cost efficient • Net2Phone – Service allows you to make free PCtotelephone calls within the United States, and international calls at discounted rates – Net2Phone and other Internet telephony services are not always compatible with systems running firewalls – ClickTogether service allows companies to add personalized voice capabilities to a Web site 2001 Prentice Hall, Inc. All rights reserved 5.8.4 Webcasting and Web Conferencing • Webcasting – Broadcasting over the Web – Businesses can stream seminars, conferences, shows, sales presentations and more though their Web sites – Live or prerecorded • Web conferencing – Allows businesses to meet and collaborate online, in real time from anywhere in the world • Evoke – Webcasting and Web conferencing 2001 Prentice Hall, Inc. All rights reserved .. .Chapter 5, Internet Hardware, Software and Communications Outline 5.7 Operating Systems 5.7.1 UNIX 5.7.2 Microsoft Windows... 5.4 Connecting to the Internet • Most home users subscribe to an Internet Service Provider (ISP) to connect to the Internet – Some charge fixed monthly fees for Internet access – Some offer free Internet access in return for personal ... Streaming media (audio and video) Internet telephony Technologies used to enhance online business communications 2001 Prentice Hall, Inc. All rights reserved 5.2 Structure of the Internet • IP address (Internet Protocol)