BIS02 Systems Architecture

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Course Material for MBA course on Business Information Systems

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BIS02 Systems Architecture

  1. 1. Business Information Systems Systems Architecture Prithwis Mukerjee, Ph.D.
  2. 2. From Science to Engineering <ul><li>Computer Science refers to Programs </li></ul><ul><ul><li>Data Structures :describes WHAT is to be processed </li></ul></ul><ul><ul><li>Algorithms : specifies HOW it is to be processed </li></ul></ul><ul><li>Information Systems Engineering refers to Systems </li></ul><ul><ul><li>Database : describes WHAT is to be processed </li></ul></ul><ul><ul><li>Applications : specifies HOW it is to be processed </li></ul></ul>
  3. 3. Integrated Systems <ul><li>First Principle </li></ul><ul><ul><li>Data must be logically distinct from Applications </li></ul></ul><ul><li>Single Tier Integrated Systems </li></ul><ul><ul><li>Need to separate data from applications </li></ul></ul><ul><ul><li>Even if they are on the same physical hardware </li></ul></ul><ul><ul><ul><li>Laptop / desktop / server </li></ul></ul></ul>
  4. 4. Two Tier : Client Server Architecture <ul><li>Data in the Server </li></ul><ul><ul><li>server software : Oracle / mySQL / SQL Server / DB2 </li></ul></ul><ul><li>Applications stored on individual machines </li></ul><ul><ul><li>Business Logic – the business rules </li></ul></ul><ul><ul><li>Presentation Logic – the GUI : windows, buttons etc </li></ul></ul><ul><li>LAN : Local Area Network </li></ul><ul><ul><li>Connects clients machines to server using TCP / IP protocols </li></ul></ul>
  5. 5. Two Tier : Client Server Architecture <ul><li>Advantages </li></ul><ul><ul><li>Convenient graphics user interface </li></ul></ul><ul><ul><ul><li>Does not place processing burden on server machine when you have hundreds of users </li></ul></ul></ul><ul><li>Disadvantages </li></ul><ul><ul><li>High Bandwidth requirements : slows down application </li></ul></ul><ul><ul><ul><li>Wide Area Network (WAN) issues </li></ul></ul></ul><ul><ul><li>Maintainance / Version Control of distributed software </li></ul></ul>
  6. 6. Three Tier Architecture <ul><li>Application is partitioned </li></ul><ul><ul><li>Business Logic kept centrally </li></ul></ul><ul><ul><ul><li>Changes to business logic done at one location </li></ul></ul></ul><ul><ul><li>Presentation Logic kept locally </li></ul></ul><ul><ul><ul><li>Data transfer over network is minimised </li></ul></ul></ul>
  7. 7. Multi-Tier Architecture <ul><li>“Internet” is no different from WAN </li></ul><ul><ul><li>Both TCP / IP but WAN is private, Internet is public </li></ul></ul><ul><ul><ul><li>Inexpensive : no need to invest in corporate network </li></ul></ul></ul><ul><ul><ul><li>Insecure : need to use security software for corporate use </li></ul></ul></ul><ul><li>Advantage </li></ul><ul><ul><li>No need for specialist software at each client location </li></ul></ul><ul><li>Disadvantage </li></ul><ul><ul><li>Business Application has to be “web enabled” </li></ul></ul>“ internet”
  8. 8. Multi Tier Architecture - Consolidation “ internet” Application server and web server physically located on same machine All three servers on same physical machine
  9. 9. Two Tier : Multiple Applications <ul><li>Multiple applications </li></ul><ul><ul><li>Have specific requirements and distinct data </li></ul></ul><ul><ul><li>Distributed across more than one machine </li></ul></ul><ul><li>These applications could be </li></ul><ul><ul><li>From different vendors or developed in-house </li></ul></ul><ul><ul><li>Based on different technology platforms </li></ul></ul><ul><ul><ul><li>Oracle ? Excel ? Java ? C++ ? </li></ul></ul></ul>Sales server Accounts server machines at Head Office machines at Sales Offices
  10. 10. Managing Complexity # 1 : RDBMS <ul><li>Advantages of an Integrated Database System </li></ul><ul><ul><li>No duplication of data </li></ul></ul><ul><ul><li>No inconsistency of data across locations / time periods </li></ul></ul><ul><ul><li>Easier to manage </li></ul></ul><ul><ul><ul><li>Backup and Restore </li></ul></ul></ul><ul><ul><ul><li>Security and user access authentication </li></ul></ul></ul>Integrated Database Oracle SQL Server MySQL machines at Head Office machines at Sales Offices
  11. 11. Managing Complexity # 2 : ERP <ul><li>Advantages of an Integrated ERP System </li></ul><ul><ul><li>Tighter integration across all functional areas </li></ul></ul><ul><ul><ul><li>No separate activity required to synchronise data </li></ul></ul></ul><ul><ul><li>Can be purchase as a single package from established vendors </li></ul></ul><ul><ul><ul><li>Benefit from best practices available with other companies </li></ul></ul></ul><ul><ul><li>Faster to implement / Easier to manage and maintain </li></ul></ul>Identical software across all company machines Integrated Database Oracle SQL Server MySQL Integrated ERP system SAP Oracle Apps
  12. 12. Handling Specialist Requirements Integrated Database Oracle SQL Server MySQL Integrated ERP system SAP Oracle Apps Identical software across all company machines Few specialists may have specific software e.g. Data Warehouse for Business Intelligence
  13. 13. Large + Complex + Distributed Systems Database Server Applications Server Wide Area Network
  14. 14. Secure, Web Based, Enterprise Systems Database Server Applications Server Firewall Servers Hackers wil get stopped by firewall “ internet”
  15. 15. Development of Application Systems Database Server Web + App Server <ul><li>Database Design and Development is based the Relational Model </li></ul><ul><ul><li>Oracle </li></ul></ul><ul><ul><li>SQL Server </li></ul></ul><ul><ul><li>MySQL </li></ul></ul><ul><ul><li>ZOHO ! </li></ul></ul><ul><li>Application Design and Development </li></ul><ul><ul><li>Java / C++ </li></ul></ul><ul><ul><li>Visual Basic </li></ul></ul><ul><ul><li>Ruby-on-Rails </li></ul></ul><ul><ul><li>ZOHO ! </li></ul></ul>“ internet”
  16. 16. Summary <ul><li>Information Systems need to be partitioned into </li></ul><ul><ul><li>Data Systems </li></ul></ul><ul><ul><li>Application Systems </li></ul></ul><ul><li>Application Architecture </li></ul><ul><ul><li>Two tier </li></ul></ul><ul><ul><li>Three tier </li></ul></ul><ul><ul><li>Three tier web based </li></ul></ul><ul><li>Data Architecture is based on the Relational Model </li></ul><ul><ul><li>Theoretically consistent </li></ul></ul><ul><ul><li>Easy to use </li></ul></ul><ul><ul><li>Widely supported by major vendors </li></ul></ul><ul><li>What is the relational model for database systems ? </li></ul><ul><ul><li>That is the next topic in the </li></ul></ul>

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