IS Today (Valacich & Schneider) 5/e Copyright © 2012 Pearson Education, Inc. Published as Prentice Hall 9/19/2015 TB-1 Technology Briefing Foundations.

IS Today (Valacich & Schneider) 5/e Copyright © 2012 Pearson Education, Inc. Published as Prentice Hall 9/19/2015 Information Systems Hardware TB-2 Input Devices  Used to enter information into a computer. Processing Devices  Transform inputs into outputs. Output Devices  Deliver information to users in a usable format.

IS Today (Valacich & Schneider) 5/e Copyright © 2012 Pearson Education, Inc. Published as Prentice Hall 9/19/2015 Input Devices TB-3 Entering text and numbers Keyboard (QWERTY)  Traditional  RF/Bluetooth  Ergonomic  Virtual Ergonomic keyboards represent a V shape to reduce stress on wrists. Virtual Laser Keyboard Source: iStockPhoto.com

IS Today (Valacich & Schneider) 5/e Copyright © 2012 Pearson Education, Inc. Published as Prentice Hall 9/19/2015 Pointing and Selecting Devices TB-4 Alternative pointing devices:  Graphics tablet  Eye-tracking device

IS Today (Valacich & Schneider) 5/e Copyright © 2012 Pearson Education, Inc. Published as Prentice Hall 9/19/2015 Entering Batch Data TB-5 Used for repetitive information  Scanners  Text recognition software  Optical character recognition  Optical mark recognition  Bar code readers  Magnetic ink character recognition  Other scanning technologies  Smart cards  Some use RFID technology for contactless transmission

IS Today (Valacich & Schneider) 5/e Copyright © 2012 Pearson Education, Inc. Published as Prentice Hall 9/19/2015 Audio Input TB-7 Audio and video input needs to be digitized.  Voice Input  Microphone  Speech recognition  Voice-to-text software  Interactive voice response (IVR) Other Forms of Audio Input  Electronic keyboards  Transfer from other devices (e.g., audio recorder).

IS Today (Valacich & Schneider) 5/e Copyright © 2012 Pearson Education, Inc. Published as Prentice Hall 9/19/2015 Video Input TB-8 Digital cameras  Digital still cameras  Digital video (DV) cameras  Streaming video  Compressed form of video that can be sent over the Internet Streaming media  Streaming video with sound

IS Today (Valacich & Schneider) 5/e Copyright © 2012 Pearson Education, Inc. Published as Prentice Hall 9/19/2015 Processing: Transforming Inputs into Outputs TB-9 Binary Codes  Binary or base-2 math (2, 4, 8, 16, 32, and so on)  Bits  Bytes  ASCII (American Standard Code for Information Interchange)  Types of encoding:

IS Today (Valacich & Schneider) 5/e Copyright © 2012 Pearson Education, Inc. Published as Prentice Hall 9/19/2015 System Unit TB-10 Houses the computer’s components  Motherboard, power supply, and fan  Central processing unit (CPU)  RAM and ROM memory  Hard drive  Optical drives  Ports  Slots  Power supply Motherboard  connects all the components that do the processing work

IS Today (Valacich & Schneider) 5/e Copyright © 2012 Pearson Education, Inc. Published as Prentice Hall 9/19/2015 Clock Speed TB-11 System clock—setting the pace for processing events.  Clock tick: single pulse.  Clock speed is measured in hertz (Hz).  One megahertz (MHz) is 1 million hertz per second. Personal computer clock speeds:  First IBM PC was 4.77 MHz.  Today, it’s 3–4 GHz.

IS Today (Valacich & Schneider) 5/e Copyright © 2012 Pearson Education, Inc. Published as Prentice Hall 9/19/2015 Primary Storage TB-13 Temporary storage of the data and programs currently in use Random-access memory (RAM) Registers Cache memory  Storage for most recently or most frequently used data  Internal cache—incorporated into the CPU (L1)  External (or secondary) cache—located close to the CPU (L2) Read-only memory (ROM)  store programs and instructions that are automatically loaded with the computer is turned on, such as the basic input/output system (BIOS)

IS Today (Valacich & Schneider) 5/e Copyright © 2012 Pearson Education, Inc. Published as Prentice Hall 9/19/2015 Secondary Storage TB-14 Hard Drives  Several magnetic disks  Read/write heads  High storage capacity (100–500GB)  Redundant array of independent disks (RAID )  Head crash occurs if read/write head touches the disk Tape drives  Used for longer-term archival storage Secondary storage is much slower than primary storage. Source: Studio Foxy\Shutterstock

IS Today (Valacich & Schneider) 5/e Copyright © 2012 Pearson Education, Inc. Published as Prentice Hall 9/19/2015 Removable Storage Media TB-15 Flash memory  Inexpensive devices with capacities of 16–128GB Optical disks  Binary data stored as pits in flat surfaces  Use laser beam technology to read and write  CD-ROMs (compact disc-read-only memory)  CD-R (compact disc-recordable)  CD-RW (compact disc rewritable)  DVD-ROM (digital versatile disk-read-only memory)  Shorter-wavelength laser beam  Digital Video Disks  Blu-Ray Magnetic tape—capacity expressed in density:  Characters per inch  Bytes per inch

IS Today (Valacich & Schneider) 5/e Copyright © 2012 Pearson Education, Inc. Published as Prentice Hall 9/19/2015 Output Devices: Video Output TB-17 Used to display information from a computer  Cathode Ray Tube (CRT)—older computer displays and TVs  Liquid Crystal Display (LCD)—newer, lighter, and thinner  Organic Light-Emitting Diodes (OLED)—even lighter  Projectors  Electronic paper (e-paper)  Example: Amazon Kindle

IS Today (Valacich & Schneider) 5/e Copyright © 2012 Pearson Education, Inc. Published as Prentice Hall 9/19/2015 System Software—Operating Systems TB-18 Common Task of an Operating System (OS)  Booting (or starting) your computer  Reading / Managing programs in memory  Managing file location  Maintaining directory structures  Formatting disks  Controlling the computer monitor  Sending documents to the printer

IS Today (Valacich & Schneider) 5/e Copyright © 2012 Pearson Education, Inc. Published as Prentice Hall 9/19/2015 Application Software Types range from large business systems to office automation to personal productivity Examples of productivity software: TB-21

IS Today (Valacich & Schneider) 5/e Copyright © 2012 Pearson Education, Inc. Published as Prentice Hall 9/19/2015 Programming Languages and Development Environments Each piece of software is developed using some programming language. Underlying programming language is invisible to the user. Source code—the program written in a programming language. Object code—machine language that the hardware can understand. 1-22

IS Today (Valacich & Schneider) 5/e Copyright © 2012 Pearson Education, Inc. Published as Prentice Hall 9/19/2015 Compilers and Interpreters TB-23 Compilers and interpreters are software designed to translate programming languages into machine code. Compilers—convert entire program source code at once. Programs are compiled before being sold to customers.

IS Today (Valacich & Schneider) 5/e Copyright © 2012 Pearson Education, Inc. Published as Prentice Hall 9/19/2015 Interpreters TB-24 Interpreter—reads, translates, and executes one line of source code at a time during operation. Each statement is converted and executed “on the fly”.

IS Today (Valacich & Schneider) 5/e Copyright © 2012 Pearson Education, Inc. Published as Prentice Hall 9/19/2015 Programming Languages TB -25 Generations of Programming Languages  1GL (1940s)—machine language (binary)  2GL (1950s)—symbolic languages  3GL (Mid-1950s)—English-like words  4GL (1970s)—outcome oriented  5GL—natural languages

IS Today (Valacich & Schneider) 5/e Copyright © 2012 Pearson Education, Inc. Published as Prentice Hall 9/19/2015 Fourth-Generation Languages TB-27 Outcome-oriented language Example: SQL for querying a database

IS Today (Valacich & Schneider) 5/e Copyright © 2012 Pearson Education, Inc. Published as Prentice Hall 9/19/2015 Fifth-Generation Languages TB-28 Called natural languages Communication in true English Used with artificial intelligence (AI) applications Example:

IS Today (Valacich & Schneider) 5/e Copyright © 2012 Pearson Education, Inc. Published as Prentice Hall 9/19/2015 Object-Oriented Languages TB-29 Most recent type of high-level programming languages Key features:  Objects  Properties (data)  Behaviors (operations)

IS Today (Valacich & Schneider) 5/e Copyright © 2012 Pearson Education, Inc. Published as Prentice Hall 9/19/2015 Visual Languages TB-31 Visual Languages  Designed for programming applications via a graphical user interface (GUI)  Microsoft examples:  Visual Basic.NET  Visual C#

IS Today (Valacich & Schneider) 5/e Copyright © 2012 Pearson Education, Inc. Published as Prentice Hall 9/19/2015 Web Development Languages TB-32 Hypertext Markup Language (HTML)  Specifies format of Web pages  Uses tags

IS Today (Valacich & Schneider) 5/e Copyright © 2012 Pearson Education, Inc. Published as Prentice Hall 9/19/2015 Java and Microsoft.NET TB-34 Java  Developed by Sun Microsystems in early 1990s  Used for dynamic content  Applets—small programs embedded in Web pages Microsoft.NET  Can be used on a variety of platforms and devices  Family of languages  C#  VB.NET

IS Today (Valacich & Schneider) 5/e Copyright © 2012 Pearson Education, Inc. Published as Prentice Hall 9/19/2015 Web Services Web-based software systems used to integrate data from different applications and databases Typically use Extensible Markup Language (XML) Advantages of Web services:  Offer interoperability between a variety of software applications on different operating systems  Allow sharing of software and services from different companies and locations  Allow the reuse of components  Easily distributed TB-35

IS Today (Valacich & Schneider) 5/e Copyright © 2012 Pearson Education, Inc. Published as Prentice Hall 9/19/2015 Scripting Languages These languages let you build programs or scripts directly into HTML page code. They are often used to check the accuracy of user-entered information, such as names, addresses, and credit card numbers. JavaScript—not the same as Java, but also allows dynamic content in Web pages. PHP —open source scripting language for Web application development.  It is often used with MySQL DBMS. Adobe Flash—another tool for adding dynamic content. TB-36

IS Today (Valacich & Schneider) 5/e Copyright © 2012 Pearson Education, Inc. Published as Prentice Hall 9/19/2015 Automated Development Environments TB-37 Computer-aided software engineering (CASE)  Used to design and implement systems  Automate activities throughout systems development process  Increase productivity  Improve quality  CASE capabilities are constantly evolving.

IS Today (Valacich & Schneider) 5/e Copyright © 2012 Pearson Education, Inc. Published as Prentice Hall 9/19/2015 Example: Use of Case Tools TB-38 High-level system design diagram Source: International Business Machines Corporation, copyright 2009 © International Business Machines Corporation.

IS Today (Valacich & Schneider) 5/e Copyright © 2012 Pearson Education, Inc. Published as Prentice Hall 9/19/2015 Open-Source Software TB-40 The source code is freely available to the general public for modification and/or use. Many large companies are involved in this effort.  IBM contributes to the further development of Linux OS.  Sun Microsystems develops and extends OpenOffice.

IS Today (Valacich & Schneider) 5/e Copyright © 2012 Pearson Education, Inc. Published as Prentice Hall 9/19/2015 Evolution of Computer Networking TB-42 Centralized computing 1940s–1970s (mainframe era) Central computer (mainframe)  Processing and storage of data Terminal  Local input/output device  Dumb and smart terminals Not a true network—no information sharing

IS Today (Valacich & Schneider) 5/e Copyright © 2012 Pearson Education, Inc. Published as Prentice Hall 9/19/2015 Evolution of Computer Networking (cont’d) TB-43 Distributed Computing  1980s  Driver: Introduction of PCs  Separate computers work on subsets of tasks.  Results are shared via network.

IS Today (Valacich & Schneider) 5/e Copyright © 2012 Pearson Education, Inc. Published as Prentice Hall 9/19/2015 Evolution of Computer Networking (cont’d) TB-44 Collaborative Computing  1990s  Synergistic form of distributed computing  Two or more computers working on a common processing task  Computers collaborate to keep employee records current.

IS Today (Valacich & Schneider) 5/e Copyright © 2012 Pearson Education, Inc. Published as Prentice Hall 9/19/2015 Types of Networks TB-45 Private Branch Exchange (PBX) Telephone system serving a particular location  Connects phones and computers  Connects PBX to outside network Limited bandwidth

IS Today (Valacich & Schneider) 5/e Copyright © 2012 Pearson Education, Inc. Published as Prentice Hall 9/19/2015 Types of Networks (cont’d) TB-46 Local Area Network (LAN) Spans relatively small area—tens of kilometers at most Computers share:  Information  Peripheral devices Usually one type of cable used Wireless Local Area Network (WLAN)

IS Today (Valacich & Schneider) 5/e Copyright © 2012 Pearson Education, Inc. Published as Prentice Hall 9/19/2015 Types of Networks (cont’d) TB-47 Campus area network (CAN)  Spans multiple buildings Wide Area Network (WAN)  Spans relatively large area  Usually connects multiple LANs  Different hardware and transmission media used  Used by multinational companies  Information transmitted across cities and countries  Four specific types of WANs  Metropolitan area networks  Enterprise networks  Value-added networks  Global networks

IS Today (Valacich & Schneider) 5/e Copyright © 2012 Pearson Education, Inc. Published as Prentice Hall 9/19/2015 Types of Networks (cont’d) TB-48 Metropolitan area networks  Usually in cities Enterprise networks  Connect disparate networks of a single organization Value-added networks (VANS)  Managed by third parties Global networks  Span multiple countries  Example: The Internet

IS Today (Valacich & Schneider) 5/e Copyright © 2012 Pearson Education, Inc. Published as Prentice Hall 9/19/2015 Types of Networks (cont’d) TB-49 Personal Area Networks (PAN)  Exchange data between computing devices  Short range radio communication— 10 meters  Examples: networking of PCs, peripheral devices, mobile phones, portable stereos, and so on  Enabling Technology: Bluetooth

IS Today (Valacich & Schneider) 5/e Copyright © 2012 Pearson Education, Inc. Published as Prentice Hall 9/19/2015 Network Services TB-50 File services  Store, retrieve, and move data files Print services  Control and manage access to printers

IS Today (Valacich & Schneider) 5/e Copyright © 2012 Pearson Education, Inc. Published as Prentice Hall 9/19/2015 Network Services (cont’d) TB-51 Message services  Store, access, and deliver data  Communication between users and applications Application services  Run software for network clients  Enable computers to share processing power  Client/server computing

IS Today (Valacich & Schneider) 5/e Copyright © 2012 Pearson Education, Inc. Published as Prentice Hall 9/19/2015 Network Operating System (NOS) NOS is a system software that controls the network and enables computers to communicate with each other. NOS enables network services. Network server NOS portion—Coordinates many functions.  User accounts  Access information  Security  Resource sharing Individual workstation NOS portion—often integrated in workstation’s OS. TB-52

IS Today (Valacich & Schneider) 5/e Copyright © 2012 Pearson Education, Inc. Published as Prentice Hall 9/19/2015 Coaxial Cable TB-54 Components:  Solid inner copper conductor  Plastic insulation  Outer braided copper or foil shield Variety of thicknesses:  Thinnet—less costly than TP but not commonly used.  Thicknet—more costly than TP.  Used for cable television and networks operating at 10–100 Mbps Source: Kaisa\Shutterstock

IS Today (Valacich & Schneider) 5/e Copyright © 2012 Pearson Education, Inc. Published as Prentice Hall 9/19/2015 Fiber-Optic Cable T B -55 Components:  Light-conducting glass or plastic  Cladding (glass)  Tough outer sheath Transmission:  Pulses of light  Immune to EMI and eavesdropping  Low attenuation  100 Mbps to more than 2 Gbps  Distance: up to 25 kilometers  Used for high-speed backbones Source: Goodshoot\Jupiter

IS Today (Valacich & Schneider) 5/e Copyright © 2012 Pearson Education, Inc. Published as Prentice Hall 9/19/2015 Wireless Media: Infrared Line of Sight TB-56 High frequency light waves Distance of up to 24.4 meters Infrared used for remote control of consumer electronic devices (TV, stereo, and so on) Relatively inexpensive Two types:  Point-to-point  Strict line of sight  Example: TV remote  Broadcast  No need for direct line of sight

IS Today (Valacich & Schneider) 5/e Copyright © 2012 Pearson Education, Inc. Published as Prentice Hall 9/19/2015 Wireless Media: High Frequency Radio TB-57 Distance between nodes 12.2–40 kilometers Ideal for mobile transmission Expensive due to cost of antenna towers Complex installation Susceptible to EMI and eavesdropping Attenuation not a problem Examples: cellular phones and wireless networks

IS Today (Valacich & Schneider) 5/e Copyright © 2012 Pearson Education, Inc. Published as Prentice Hall 9/19/2015 Cellular Network TB-58 Coverage area divided into cells  Low-powered radio antenna/receiver  Cells controlled by a central computer Unique frequency assigned for duration of phone call Mostly digital today  Less static  Data transmission capability  Wider reception range

IS Today (Valacich & Schneider) 5/e Copyright © 2012 Pearson Education, Inc. Published as Prentice Hall 9/19/2015 Wireless Local Area Networks (WLAN) WLAN is based on a family of standards called 802.11. They have transmission speeds up to 300 Mbps. Ease of installation makes them popular for home use. Older buildings and homes do not have a wired infrastructure, making WLAN attractive. TB-60

IS Today (Valacich & Schneider) 5/e Copyright © 2012 Pearson Education, Inc. Published as Prentice Hall 9/19/2015 Wireless Media: Microwave TB-61 High-frequency radio  Terrestrial microwave  Line-of-sight  Transmission up to 274 Mbps  EMI and eavesdropping problems  Attenuation a problem over long distances  Cross inaccessible terrain  Cost depends on distance  Alternative when cabling too expensive

IS Today (Valacich & Schneider) 5/e Copyright © 2012 Pearson Education, Inc. Published as Prentice Hall 9/19/2015 Microwave (II): Satellite Microwave TB-62 Relay station transfers signals between antennae on earth and satellites in the orbit.  Propagation delay  Satellites orbit 400–22,300 miles above earth  Typically 1–10 Mbps, up to 90 Mbps  Can access very remote areas  Viable for TV, radio, digital radio  Susceptible to EMI and eavesdropping

IS Today (Valacich & Schneider) 5/e Copyright © 2012 Pearson Education, Inc. Published as Prentice Hall 9/19/2015 Network Standards and Technologies TB-65 Standards ensure interpretability and compatibility of network devices. Standards were established by IEEE. The initial three major standards for LANs are:  Ethernet  Token ring  ARCnet Each standard combines:  media access control technique  network topology  transmission media Protocols are implemented in NOS and/or local OS. Software blended with hardware to implement protocols

IS Today (Valacich & Schneider) 5/e Copyright © 2012 Pearson Education, Inc. Published as Prentice Hall 9/19/2015 Media Access Control TB-66 Problem: Collision occurs when two workstations transmit data simultaneously. Media Access Control: Set of rules that govern access. Types of Media Access Control:  Distributed  One workstation at a time with access  Authorization transferred sequentially  Access requires a token  Random access  Any workstation can transmit if medium is available  No permission required  Access via carrier sense multiple access (CSMA)

IS Today (Valacich & Schneider) 5/e Copyright © 2012 Pearson Education, Inc. Published as Prentice Hall 9/19/2015 Network Topologies: Star TB-67 All workstations are connected to a central hub. Active hubs amplify transmission. Star topologies are easy to lay out and modify. They are the most costly because they have the greatest amount of cabling. Failure of hub can cause network failure.

IS Today (Valacich & Schneider) 5/e Copyright © 2012 Pearson Education, Inc. Published as Prentice Hall 9/19/2015 Network Topologies: Ring TB-68 In a ring topology, messages move in one direction around a closed loop. Regeneration process enables coverage of large distances. It requires relatively little cabling. Failure of one node can cause network failure.  Self-healing ring (two rings, flowing in different directions); failure of single node does not fail the network It is, however, difficult to modify. Token passing is used to regulate traffic.

IS Today (Valacich & Schneider) 5/e Copyright © 2012 Pearson Education, Inc. Published as Prentice Hall 9/19/2015 Network Topologies: Bus TB-69 Bus topology uses an open- ended line. It is the easiest to extend. It has the simplest wiring layout. All nodes can receive the same message at the same time. Network faults are difficult to diagnose. Bus networks use variants of CSMA for media access control.

IS Today (Valacich & Schneider) 5/e Copyright © 2012 Pearson Education, Inc. Published as Prentice Hall 9/19/2015 Network Topologies: Mesh TB-70 A mesh network consists of devices fully or partially connected to each other.  Full mesh  Partial mesh Mesh networks provide short routes between nodes. They also provide many possible routes through the network. Mesh networks perform well in heavy traffic. Most WANs use a partial mesh design.

IS Today (Valacich & Schneider) 5/e Copyright © 2012 Pearson Education, Inc. Published as Prentice Hall 9/19/2015 Network Protocols Agreed-upon formats for transmitting data between connected computers Ensure successful communication between computers Allow packets to be correctly transmitted between computers Provide specifications for:  Connections between computers  Error-checking  Signifying end of message  Verifying reception of message TB-71

IS Today (Valacich & Schneider) 5/e Copyright © 2012 Pearson Education, Inc. Published as Prentice Hall 9/19/2015 The Open System Interconnection (OSI) Model TB-72 Defined by International Organization for Standardization (ISO) The OSI model is divided into seven layers, each building on the functions of the lower layer.

IS Today (Valacich & Schneider) 5/e Copyright © 2012 Pearson Education, Inc. Published as Prentice Hall 9/19/2015 Ethernet TB-74 Ethernet is a LAN protocol that was developed by Xerox in 1976. Bus network topology Random access control Originally: 10 Mbps Later: 100Base-T (Fast Ethernet)—100 Mbps Latest: 10 Gigabit Ethernet—10,000 Mbps Newer Ethernet use routers and switches to allow full duplex transmission. Most PCs include an Ethernet card.

IS Today (Valacich & Schneider) 5/e Copyright © 2012 Pearson Education, Inc. Published as Prentice Hall 9/19/2015 TCP/IP Transmission Control Protocol/Internet Protocol The protocol of the Internet Allows communication between different interconnected networks IP was developed via DARPA project by Vinton Cerf and Robert Kahn. TB-75

IS Today (Valacich & Schneider) 5/e Copyright © 2012 Pearson Education, Inc. Published as Prentice Hall 9/19/2015 Connectivity Hardware TB-76 Network interface card (NIC)  PC expansion board that enables a PC to connect to a network  Each NIC has a unique MAC address as an identifier. Connectors  Terminate cables so that they can be plugged into a NIC or other network components  T-connectors for coax cable  RJ-45 connectors for TP cable Computers use digital signals.  Phone lines can only handle analog signals.  Modems convert digital signals into analog and analog systems into digital.

IS Today (Valacich & Schneider) 5/e Copyright © 2012 Pearson Education, Inc. Published as Prentice Hall 9/19/2015 Modems TB-77 Modems enable transmission of data over telephone lines. Modulator—digital signal converted to analog. Demodulato—analog signal converted to digital.

IS Today (Valacich & Schneider) 5/e Copyright © 2012 Pearson Education, Inc. Published as Prentice Hall 9/19/2015 Connecting Independent Networks TB-79 Routers interconnect independent networks. Routers are the fundamental building blocks of Internet. Router:  Special-purpose computer  Only jobs:  Interconnect networks  Forward data packets

IS Today (Valacich & Schneider) 5/e Copyright © 2012 Pearson Education, Inc. Published as Prentice Hall 9/19/2015 Backbone Networks TB-80 Manage bulk of network traffic, high speed Use high-speed media such as fiber optic cable Source: Douglas E. Comer, The Internet Book, 2 nd ed. (Upper Saddle River, NJ: Prentice Hall, 1997)

IS Today (Valacich & Schneider) 5/e Copyright © 2012 Pearson Education, Inc. Published as Prentice Hall 9/19/2015 Who Manages the Internet? TB-81 National and international committees Internet Assigned Numbers Authority  Responsible for managing global and country code top- level domains and IP number space assignments  Maintains Domain Name System (DNS) root database maintenance  Match domain names with IP addresses  www.apple.com = 17.251.200.32

IS Today (Valacich & Schneider) 5/e Copyright © 2012 Pearson Education, Inc. Published as Prentice Hall 9/19/2015 Who Manages the Internet? (cont.) TB-82 InterNIC  Government-industry collaboration  Created by NSF in 1993 Internet Corporation for Assigned Names and Numbers (ICANN)  Manages IP addresses, domain names and root server system IPv6 created to meet growing demand for Internet addresses

IS Today (Valacich & Schneider) 5/e Copyright © 2012 Pearson Education, Inc. Published as Prentice Hall 9/19/2015 How to Connect to the Internet TB-83 Internet service provider (ISP) ISPs connect to each other through Network access points (NAPs)  Determine how traffic is routed  Key component of the Internet backbone  Hierarchical structure

IS Today (Valacich & Schneider) 5/e Copyright © 2012 Pearson Education, Inc. Published as Prentice Hall 9/19/2015 Business Internet Connectivity TB-85 Increased needs for bandwidth High-speed options  T1 Lines  1.544 Mbps  T3 Lines  45 Mbps  Asynchronous transfer mode (ATM)  OC—Optical Carrier

IS Today (Valacich & Schneider) 5/e Copyright © 2012 Pearson Education, Inc. Published as Prentice Hall 9/19/2015 Asynchronous Transfer Mode (ATM) TB-86 Transmission of voice, video, and data Up to 2.2 Gbps Used for LANs and WANs Integration of disparate networks Packet-switched transmission  Fixed-length cells (53 bytes) Can be used without routers Especially interesting for movie and entertainment industries

IS Today (Valacich & Schneider) 5/e Copyright © 2012 Pearson Education, Inc. Published as Prentice Hall 9/19/2015 The Future of Connectivity TB-88 New innovations  Broadband over power lines  Power line communication  Use of power distribution wires  Current rates: 5 Mbps  Infrastructure readily available  HomePlug devices —83–200 Mbps  WiMax—Worldwide Interoperability for Microwave access  “Last mile” wireless  High-speed stationary wireless  Does not require line-of-sight  Currently expensive

IS Today (Valacich & Schneider) 5/e Copyright © 2012 Pearson Education, Inc. Published as Prentice Hall 9/19/2015 Current State of Internet Usage TB-89 The most prominent global network 1.8 billion people  26 percent of world’s population have access at home  400 percent increase since 2000  Asia—most users  North America—largest percentage of population are users (76.2 percent)  Africa—smallest percentage (8.7 percent)  Rapid growth—1810 percent

IS Today (Valacich & Schneider) 5/e Copyright © 2012 Pearson Education, Inc. Published as Prentice Hall 9/19/2015 Growth in Internet Servers (Hosts) TB-90 Source: Internet Systems Consortium. http://www.isc.org/solutions/surveyhttp://www.isc.org/solutions/survey

IS Today (Valacich & Schneider) 5/e Copyright © 2012 Pearson Education, Inc. Published as Prentice Hall 9/19/2015 Database Design TB-91 Poor data model will result in data that are:  inaccurate,  redundant, and  difficult to search. Poorly designed database is difficult to maintain and process. Entities have attributes.  Each instance of an entity must have a unique identifier.

IS Today (Valacich & Schneider) 5/e Copyright © 2012 Pearson Education, Inc. Published as Prentice Hall 9/19/2015 Identifying Records TB-93 Uniquely identifying records:  Primary Key  Unique identifier  Examples: Student ID number; social security number  Combination primary key  Combination of two or more attributes  Example: Identifying a student’s grade for a particular class for a particular term Identifying records that share a common value  Secondary Key  Attribute not used as a primary key  Example: Major

IS Today (Valacich & Schneider) 5/e Copyright © 2012 Pearson Education, Inc. Published as Prentice Hall 9/19/2015 Associations (Relationships) TB-94 Used to relate information between tables Needed to retrieve information Example: Basketball league database

IS Today (Valacich & Schneider) 5/e Copyright © 2012 Pearson Education, Inc. Published as Prentice Hall 9/19/2015 Example: Basketball League TB-95 Each table contains important data. No way to learn which team plays in a specific stadium Need to make associations.

IS Today (Valacich & Schneider) 5/e Copyright © 2012 Pearson Education, Inc. Published as Prentice Hall 9/19/2015 Example: Basketball League (cont’d) TB-96 Foreign keys  Attributes used to link tables.  Primary key is in one table, foreign key is in another.  Need to create additional entity for many-to-many relationships.

IS Today (Valacich & Schneider) 5/e Copyright © 2012 Pearson Education, Inc. Published as Prentice Hall 9/19/2015 Entity-Relationship Diagram TB-97 Used to show associations between entities Important when designing complex databases  Entities: represented by boxes  Relationships: represented by lines Associations

IS Today (Valacich & Schneider) 5/e Copyright © 2012 Pearson Education, Inc. Published as Prentice Hall 9/19/2015 The Relational Model TB-98 Primary DBMS approach (RDBMS) 3 dimensions  Entities represented as 2-dimensional tables  Rows = records  Columns = attributes  Tables joined based on common columns (3 rd dimension) Good design eliminates redundancy.

IS Today (Valacich & Schneider) 5/e Copyright © 2012 Pearson Education, Inc. Published as Prentice Hall 9/19/2015 Data Redundancy TB- 99 Problematic if an attribute has to be changed  Need to change in multiple locations  Example: instructor’s phone number

IS Today (Valacich & Schneider) 5/e Copyright © 2012 Pearson Education, Inc. Published as Prentice Hall 9/19/2015 Normalization TB- 100 Eliminate unnecessary redundancy.  Create separate tables.  Data only needs to be changed in a single location.

IS Today (Valacich & Schneider) 5/e Copyright © 2012 Pearson Education, Inc. Published as Prentice Hall 9/19/2015 TB-1 Technology Briefing Foundations.

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IS Today (Valacich & Schneider) 5/e Copyright © 2012 Pearson Education, Inc. Published as Prentice Hall 9/19/2015 TB-1 Technology Briefing Foundations.

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