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Introduction to Information Technology for Business People. Brad Wheeler, Ph.D. Information Systems School of Business bwheeler@indiana.edu. Agenda - Client/Server. The Client/Server Model On the Client Side... On the Server Side... Middleware: The MESSY Stuff in Between
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Introduction to Information Technology for Business People Brad Wheeler, Ph.D. Information Systems School of Business bwheeler@indiana.edu
Agenda - Client/Server • The Client/Server Model • On the Client Side... • On the Server Side... • Middleware: The MESSY Stuff in Between • Coping with the Now and the Not Yet(e.g., Java!)
C/S is about Software Separation of programs into independent communicating modules DC is about Hardware Hardware and network design where multiple, physically independent computers cooperate to accomplish a task C/S g Distributed Computing
The Client/Server Model • Partitions (tiers) business logic, data, and presentation into independent and reusable modules • Based on loose coupling of software • Can be implemented on any hardware platform • Natural fit with the distributed computing in the Network Era
Server(s) Client(s) GUI/Presentation/ Processing? Application Logic + Shared Data Server(s) Server Client(s) GUI/Presentation/ Processing? Application Logic Shared Data 2-, 3-, and N-tiered C/S 2 Tier 3 Tier
(Blank) Costs Less! NonMainframeMulti-tier Costs Mainframes Single-tier High Low # Transactions
On the Client Side... • Clients should handle user dialog, presentation, some processing • “Fat” v. “Thin” Clients • “Proprietary” v. “Standard” Clients • Are web browsers clients? • Example: United Airlines & Expedia
United Airlines & Expedia Servers Proprietary Client UA Light Traffic GUI, Presentation & Processing Web Browsers Servers Expedia GUI & Presentation NO Processing! Heavy Traffic
On the Server Side... • Shared Databases • On-Line Transaction Processing • Groupware (mail, calendaring, conferencing) • HTML Documents • Objects! Objects! Objects!
Server Duties • Waits for client requests • Invokes programs and resources to fill requests • Provides security and transaction integrity • May act as client to request resourcesfrom another server on behalf of a client
The Middleware Minefield! Client(s) Server(s) Middleware • Service Specific • Network Op Systems • Transport Stack
Simplified Middleware... • Service Specific • ODBC, ORB, HTTP, Mail • Network Operating System • Directory Services, File Systems, Security, Messaging, Remote Procedures • Transport Stack • TCP/IP, NetBIOS, IPX/SPS, SNA
C/S: Now and the Not Yet Java Java Beans Applets Object Request Broker Components Active-X Applications
Recommended Readings • Orfali R., Harkey, D., & Edwards, J. (1996). The Essential Client/Server Survival Guide, 2nd Edition, Wiley: New York. 0-471-15325-7 • $26.34 at http://www.barnesandnoble.com • $27.99 at http://www.amazon.com • InfoWorld http://www.infoworld.com for C/S news • InfoWorld 1997 Opinion columns by Bob Lewis
Presentation On-Line Powerpoint slides at http://ais-notes.bus.indiana.edu/bcw/bwheeler.nsf (under Presentations)