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Introduction to Information Systems COMPLETE Study Guide [4.0ed the final]

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Boston University
Information Systems
SMG IS 223

IS 12: Hardware/Software Information Technology Infrastructure: the shared technology resources that provide the platform for the firm’s specific information system applications Evolution of IT Infrastructure general-purpose mainframeminicomputer computingpersonal computers client/server networksenterprise computingcloud computing -Mainframe era -period of very centralized computing -manufacturer of hard/software provided all elements of infrastructure -Minicomputer Era -offered powerful machines at lower prices than mainframes -made decentralization possible (customized to certain needs of different departments) -Personal Computer Era -Wintel PC: standard desktop personal computer -rise of personal software tools: word processors, spreadsheets, etc. -Client/Server Era -desktops/laptops called clients are networked to powerful server computers that provide services/capabilities -client is user point of entry -Server refers to both software application and the physical computer -multitier client/server architecture: work of entire network is balanced over several levels of servers -1 layer: web server software is responsible for locating and managing stored web pages -2 layer: application server handles all application operations between a user and an organization’s back-end business systems -Enterprise Computing Era -firms turned to networking standards and software tools that could integrate disparate networks and applications throughout the firm into an enterprise-wide infrastructure -uses TCP/IP -Cloud Computing -model of computing where firms and individuals obtain computing power and software applications over the Internet Technology Drivers of Infrastructure Evolution -Moore’s Law and Micro-pressing Power -Moore’s Law: # of components on a chip with the smallest manufacturing costs doubles every two years -variations: (1) power of microprocessor doubles every 18 months (2) computing power doubles every 18 months (3) price of computing falls by half every 18 months -Nanotechnology: uses individual atoms and molecules to create computer chips and other devices that are thousands of times smaller than current technologies permit -The Law of mass Digital Storage -amount of digital info is roughly doubling every year -cost of storing digital info is falling at 100% per year -Metcalfe’s Law : increasing returns to scale (value) as more and more people join the network -rapid decline in costs of communication -technology standards: specifications that establish the compatibility of products and the ability to communicate in a network -result in powerful economies of scale Infrastructure Components: 1. Computer Hardware Platforms -blade servers: ultrathin computers consisting of a circuit board processors, memory, and network connections stored in racks (much more space efficient) 2. Operating System Platforms -manage resources and activities of computer (allows multiple programs to share a single computer) 3. Enterprise Software Applications 4. Data Management and Storage -Storage Area Networks: connect multiple storage devices on a separate high-speed network 5. Networking/Telecommunications Platforms 6. Internet Platforms -Web Hosting Service: maintains large web server and provides fee-paying subscribers with space for a website 7. Consulting and System Integration Services -Legacy Systems: generally older transaction processing systems created for mainframe computers that continue to be used to avoid the high cost of replacing or redesigning Contemporary Hardware Platform Trends -Emerging Mobile Digital Platform -netbooks: small, low-cost subnotebooks -Grid Computing: connecting geographically remote computers into a single network to create a virtual supercomputer by combining the computational power of all computers on the grid -most computers in us only use 25% of processing units -grid computing uses the idleness for other tasks -Cloud Computing and the Computing Utility -firms do not need to make large investments in hardware/software -Computing Utility: pay only for computing power that firm actually uses -Autonomic Computing: industry-wide effort to develop systems that can configure themselves, optimize and tune themselves, and heal/protect themselves from outside intruders/self-destruction -Virtualization and Multi-core Processors -virtualization: process of presenting a set of computing resources so that they can be accessed -breaks physical and geographic boundaries -Multi-core Processors: integrated circuit to which two or more processors have been attached for enhanced performance, reduced power consumption and more efficient simultaneous processing of multiple tasks Contemporary Software Platform Trends -Open Source Software: produced by a community of several programmers around the world -FREE and can be modified by users -mostly based on Linux or Unix -premise: better than commercial software b/c thousands of programmers can perfect software without pay -Linux: example of open source software -Software for the Web -Java: operating system-independent, processor-independent, object-oriented programming language that has become the leading interactive programming environment for the Web -designed for any computer -can handle text, data, graphics, sound, and video -Web Browser: easy-to-use software tool with a graphical user interface for displaying Web Pages and for accessing the web -Ajax (asynchronous JavaScript and XML): web development technique for creating interactive web apps -Web services: loosely coupled software components that exchange info with each other -Extensible Markup Language (XML): language foundation for web services -more powerful/flexible markup language than hypertext (HTML) -HTML: page description language for specifying how text, graphics, and sound are placed on web page -Service Oriented Architecture: set of self-contained services that communicate with each other to create a working software application -Mash ups: mix and match these software components to create their own customized applications -Widgets: small software programs that can be added to web pages or placed on the desktop to provide additional functionality -Software as a Service: services for delivering and providing access to software remotely as a web- based service -Outsourcing -service level agreement: formal contract between customers and service providers IS 13: Telecommunications Networking and Communication Trends -2 traditional types of networks: 1.Telephone networks: handles voice communication 2. Computer networks: handles data traffic -Both voice and data communication networks have become faster, more portable, cheaper -mobile wireless broadband internet -Network Interface Card (NIC): network interface device located in each computer on a network -Network Operating System (NOS): routes and manages communications on the network and coordinates resources -can be on every computer on network or on a server computer -ex) Microsoft Windows Server, Linux, Novell NetWare -Hub: simple device that connects network components and sends packet of data to all other connected devices -Switch: contains more intelligence than a hub and can filter and forward data to a specified location on network -Router: communications processor used to route data to different networks -a major problem facing firms today is how to integrate all the different communication networks and channels -internet technologies will make this easier Key digital Networking Technologies -Contemporary digital networks/internet is based on THREE core technologies: 1.Client/Server Computing: distributed computing model in which some of the processing power is located within small, inexpensive client computers (has largely replaced centralized computing) 2.Packet Switching: method of slicing digital messages into “packets” and sending them along different communication paths as they become available, and then reassembling the packets at their destination 3.TCP/IP and Connectivity: common, world-wide standard protocol -protocol: set of rules/procedures governing transmission of data between two points in a network -Transmission Control Protocol (TCP): handles movement of data between computers -Internet Protocol (IP): handles delivery of packets (includes assembly/disassembly of packets in transmission) -TCP/IP Reference Model 1. Application layer: enables programs to access other layers and defines protocols -ex) Hypertext Transfer Protocol (HTTP) 2. Transport Layer: provides application layer with communication/packet services (includes TCP) 3. Internet Layer: addresses/routes/packages data packets called IP datagrams (includes IP) 4. Network Interface Layer: places packets on and receiving them from the network medium Signals: TWO ways to communicate a message in a network 1. Analog Signal: continuous waveform that passes through a comm. medium and has been used for voice comm. -ex) telephone, ipod earphone, computer speakers 2. Digital Signal: discrete, binary waveform that communicates info as strings of one bit and zero bit states (represents on and off electrical pulses) -modem (modulator-demodulator): translates digital signals into analog form Types of Networks -Local Area Networks (LAN): connect personal computers/other digital devices within a half-mile (500 meter) radius -can connect to WANs via the internet -Ethernet is dominant LAN standard -Alternatively, LANs can use peer-to-peer architecture which treats all processors equally and is used primarily in small networks with 10 or fewer users -Star topology: all devices in a network connect to a single hub -Bus topology: one station transmit signals, which travel in both directions along a transmission segment (common) -Ring topology: connects network components in a closed loop (messages pass from computer to computer in one direction) -Wide Area Networks (WAN): span broad geographic distances (ex. Internet) -Metropolitan Area Network (MAN): only spans a metropolitan area, usually a city and its major suburbs Physical Transmission Media: -Twisted Wire: strands of copper wire twisted in pairs and is an older medium (speeds up to 1Gbps) -Coaxial Cable: thickly insulated copper wire and can transmit more data than twisted wire (speeds up to 1Gbps) -Fiber Optic Cable: bound strands of clear glass fiber (faster, lighter and more durable than wire media) -Microwave: transmit high-frequency radio signals through the atmosphere and used for long distance, point- to-point communication Transmission Speed -volume of info is measure in bits per second (bps) -hertz: one hertz is equal to one cycle of the medium -bandwidth: range of frequencies that can be accommodated on a particular telecommunications channel Internet -Internet Service Provider (ISP): commercial organization with a permanent connection to the Internet and sells temporary connections -Digital Subscriber Line (DSL): operate over existing telephone lines to carry voice, data, and video -Cable Internet Connections: provided by cable television vendors use digital cable coaxial lines -T1/T3: international telephone standards for digital communication (promise certain speeds) -based on TCP/IP protocol -Internet Protocol (IP) Address: 32-bit number represented by 4 strings of numbers ranging from 0 -255 separated by periods -Domain Name System: converts IP addresses to domain names -hierarchical structure see p. 201 -World will run out of available IP addresses by 2012/2013 -Internet Protocol version 6 (IPv6): 128-bit addresses (more than quadrillion) -internet2: consortia of universities, private businesses, and government in US that are working on a new high- bandwidth version of the internet -Unified Communications: integrates disparate channels for voice, data, instant messaging, email, and electronic conferencing into a single experience -Virtual Private Network (VPN): secure, encrypted network that has been configured within a public network to take advantage of the economies of s
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