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BASIC INFORMATION TECHNOLOGY CONCEPTS IS 524. Chandra S. Amaravadi. OUTLINE OF THIS PRESENTATION. Introduction Hardware Software Networks The internet IS Architectures. INTRODUCTION. information technologies (IT) are building blocks consist of HW, SW, networks etc.
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BASIC INFORMATION TECHNOLOGY CONCEPTS IS 524 Chandra S. Amaravadi
OUTLINE OF THIS PRESENTATION • Introduction • Hardware • Software • Networks • The internet • IS Architectures
INTRODUCTION • information technologies (IT) are building blocks • consist of HW, SW, networks etc. • HW & networks have micro-processor based components • IS consists of IT!
COMPUTER TYPES Computers can be classified by number of users: • Single user systems • PCs, laptops, notebooks and handhelds (smart phones) • Workstations • Multi-user systems • Mainframes(legacy system, host) • Servers
HARDWARE ORGANIZATION MEMORY UNIT Central Processor INPUT OUTPUT ALU CU ROM RAM Cache STORAGE
HARDWARE Physical components of a computer system ALU – processes instructions using logic circuits RAM – stores current data & programs Control Unit – controls operations by sending signals Clock -- ensures timing of operations I/O devices -- keyboard, secondary storage, monitor Bus wires -- transmit data (in the form of 0’s & 1’s)
HARDWARE ISSUES • performance: how to increase it? • reliability: how to achieve it? • scalability: adding capacity • security: physical security, • avoiding viruses/intrusions
SOFTWARE Software/SW Program: Detailed instructions to the computer to control information processing operations. • generally written in a programming language • program listing is called _____ ______. • converted to binary (“m/c” language or _____ • ______) and executed • component is called compiler
SOFTWARE Software Open Source Application Software System Software “business” or “productivity” Utility Compilers Operating Systems Customized applications!
PROGRAMMING LANGUAGES Generations of Programming Languages 1st - Machine 2nd - Assembly 3rd - COBOL, Fortran, “C” 4th - SQL, Java script 5th - Prolog, Java, VC++, Python
OPERATING SYSTEM • Software to control system components • Runs the hardware • CPU, memory etc. • Interacts/monitors users • key board commands • passwords etc.
COMPILERS AND UTILITY SW Compiler converts program to m/c. Programs written in languages: Utility software perform support functions e.g. virus checking, backup etc.
APPLICATIONS SOFTWARE CUSTOMIZED APPLICATIONS Inventory Accounting Invoicing ……. BUSINESS SOFTWARE Word processing Spreadsheet Email …….. OPEN SOURCE SOFTWARE APPLICATION SOFTWARE SYSTEM SOFTWARE HARDWARE
BUSINESS SOFTWARE Software used for a business purpose (productivity). • available for a number of functions • example Powerpoint, Word etc. • integrated under Windows • highly finished -- common “look & feel” • not available for every function • licensing and upgrades are common issues
CUSTOMIZED SOFTWARE Special purpose software for specific business function. • Example rate quote, claims processing etc. • Mostly developed in-house or by third party • sometimes customized from business software • current development is in OO languages • More expensive than business sw • In-house applications have components: • interface • business logic • database access
OPEN SOURCE SOFTWARE Software available without licensing fee. • aka “shareware” • frequently comes with source code • authored by developers but an institution “governs” • Linux, red hat, Open Source foundation • sometimes subscription/nominal fees • bugs, version proliferation and support are common issues
A BASIC COMMUNICATION NETWORK Communication devices Medium Terminals Host
COMMUNICATIONS COMPONENTS.. Terminals Terminals are the devices used by users to initiate communications. CommunicationsDevices Perform support functions at each end (e.g. conversion from digital to wireless, multiplexing). Medium Physical medium over which transmission takes place, mostly cable, fiber optic or microwave/satellite. Host computers Provide communication services Communications software Performs network management and protocols (set of signals exchanged before data is sent)
TYPES OF NETWORKS Networks are classified as follows: • LANs • Wireless LANs • WANs • VANs • VPN LAN – local area network WAN – Wide area network VAN – Value added network VPN – Virtual private network
Printer A Wireless Network Cable modem or DSL Wireless Key security Router Router routes traffic to device ISP Wireless Card Carries out communication functions & protocols
WIDE - AREA NETWORK (WAN) In WANs communications take place across geographic distances and often involve multiple modes
VIRTUAL PRIVATE NETWORK (VPN) A “private network”/tunnel created within a public infrastructure using encryption
BACKGROUND The internet had a long history with various developments • Started as a research network • first as Arpanet, then bitnet, NSF net • Released into public domain in 1993 • Publicly owned (ATT, Verizon etc.) • HTML in 1991 • Web technology (web pages) in 1992 • 3b users on the web world wide
INTERNET PRINCIPLE NODE (173.75.5.8) NODE (143.45.56.9) NODE NODE Data is broken into packets, routed by routers and sent to destination.
INTERNET PRINCIPLES • Thousands of networks connected • networks have hosts • hosts can be PCs, web servers, mainframes • each “host” has a unique IP address • TCP/IP protocols are used for transmission • Data sent as packets • Addressed by hosts • Routed by routers
THE INTERNET ARCHITECTURE The internet connects web servers and web clients, via a network of networks DNS server Router INTERNET Host/nodes Web server Web client Web client Web client
SOME TERMINOLOGY Browser: A program to access and display web pages. Web-server: computers which can host web sites. Web-client: A computer used to access a web site. Web-site: A location on the WWW with a domain address/a web host. DNS: Domain Name Server or Name server – reference for web site addresses Router: A device to route data packets to destinations. Node: An addressable location on the internet. Could be a host or web server WWW: A network of web servers,
IS ARCHITECTURE Hardware arranged in different configurations CENTRALIZED:Processing carried by one or more “hosts” (“host-based arch.) DISTRIBUTED:Processing shared by several hosts connected by a network CLIENT SERVER:Processing carried by one or more “servers” CLOUD: Applications and data hosted on the internet
CENTRALIZED VS DISTRIBUTED Host Centralized Distributed
CLIENT SERVER ARCHITECTURE CLIENT CLIENT requests SERVER e.g. mail, database data/service CLIENT CLIENT:Any computer that requires a service. SERVER: Any computer that can fulfill a request.
CLOUD ARCHITECTURE CLIENT CLIENT requests Cloud data/service CLIENT Internet
CONTEMPORARY ARCH. Cloud Sales Order Fulfillment Internet Service Orderentry Intranet web server Database server Apps. server Internet web server Firewall Purchasing Inventory Web design printer support printer Warehousing Finance Marketing Financial planning Accounts payable Central hub Shipping Accounts receivable Research & planning Credit printer printer Sales Advertising Accounting
DISCUSSION QUESTIONS • Why is hardware important for information systems? • What issues does software present to organizations? • What might be the sixth generation programming language? • When in MS Word, user presses “save” what sw are involved in saving? • What happens to the internet if all DNS servers fail? • In a certain less developed country there is limited access to internet. What should the government do? • Is it possible for a country to block off internet traffic coming from outside?, how? • In McDonald’s restaurants, all local processing in each of their restaurants is done by a local host, but financial data is sent to a mainframe at HQ; what arch. is this?