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!

HARDWARE

VARIETY OF HARDWARE

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 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) and executed component is called compiler

SOFTWARE applications! Software Application Software Open Source System Software “business” or “productivity” Utility Compilers Operating Systems Customized applications!

OPERATING SYSTEM Software to control system components Runs the hardware CPU, memory etc. Interacts/monitors users key board commands passwords etc.

PROGRAMMING LANGUAGES Generations of Programming Languages 1st - Machine 2nd - Assembly 3rd - COBOL, Fortran, “C” 4th - SQL, Java script 5th - Prolog, Java, VC++, Python

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

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

NETWORKING

A BASIC COMMUNICATION NETWORK Communication devices Medium Terminals Host

COMMUNICATIONS COMPONENTS.. Terminals Terminals are the devices used by users to initiate communications. Communications Devices 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 LANs Wireless LANs WANs VANs VPN 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

A Wireless Network Printer ISP Wireless Card 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

INTERNET

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 NODE (173.75.5.8) (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 ARCHITECTURES

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 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 Finance Marketing Internet Service Order entry 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? When in MS Word, user presses “save” what sw is involved? 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? What correspondence is there between diagram on last page and organizational concepts (which concepts)? explain