Client / Server 2110213 Information System Organization Natawut - PowerPoint PPT Presentation

Client / Server 2110213 Information System Organization Natawut Nupairoj, Ph.D. Department of Computer Engineering Chulalongkorn University IS Components Natawut Nupairoj, Ph.D. 1

What is Client/Server? If the client’s The client request is computer sends a appropriate, the request for service server provides the to the server over a service. network. Networks Server Client IS Components Natawut Nupairoj, Ph.D. 2

Why Client/Server? � Shared data � Shared resources � Storages � Printers � Security control IS Components Natawut Nupairoj, Ph.D. 3

Popular Servers � Web Server � Database Server � File Server � App Server � Authentication Server (Radius / LDAP) IS Components Natawut Nupairoj, Ph.D. 4

Functional Components � Presentation Logic: User Interfaces. � Business Logic: Application Programs and Services. � Data Logic: Databases. IS Components Natawut Nupairoj, Ph.D. 5

Dumb Terminal (single-tier) � Server with “dumb” terminals. key “a” display “a” Server Terminal IS Components Natawut Nupairoj, Ph.D. 6

Example: Registration System � Add a course: Check dept. Check preq. Check total credit “select a course” “2110213” “course added” Server Terminal IS Components Natawut Nupairoj, Ph.D. 7

Pros and Cons � Pros: � Single place, easy to control. Presentation Business Data � Cons: � Expensive, big spaghetti bowl, inflexible, lack of applications, take long time to develop. IS Components Natawut Nupairoj, Ph.D. 8

Dumb Server (Two-Tier) � Database server with fat clients VB / Developer 2000 client program + SQL database. � database command result PC Client DB Server (Reg Program) IS Components Natawut Nupairoj, Ph.D. 9

Example: Registration System � Add a course: Check dept… ok! Check preq… ok! Check total credit < 22 ? get all my courses 2110211, 2110213, … PC Client DB Server (Reg Program) IS Components Natawut Nupairoj, Ph.D. 10

Pros and Cons � Pros: � Simple to develop (initially). � Cons: � Poor scalability. � Poor manageability and deployability. IS Components Natawut Nupairoj, Ph.D. 11

Shared Processing (Three-Tier) � Database + Web server / App server + Browsers (Thin clients). db command POST result HTML DB Server Web Server / PC Client AppServer (Browser) IS Components Natawut Nupairoj, Ph.D. 12

Example: Registration System Check dept… ok! Check preq… ok! Check total credit < 22 ? add 2110213 get my all courses HTML 2110211, … “Course added” DB Server Web Server / PC Client AppServer (Browser) IS Components Natawut Nupairoj, Ph.D. 13

Pros and Cons � Pros: B � Scalability. App Svr � Flexible. � Simple to manage. DB Web App B � Great for integration. Svr Svr Svr � Cons: App � Slightly difficult to Svr develop (initially). B IS Components Natawut Nupairoj, Ph.D. 14