Information System Architectures Traditional architectures, ClientserverPointtoPoint architectures,

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Information System Architectures (Traditional
architectures, Client/server/Point-to-Point 
architectures, Distributed architectures) 

• Distributed by Zelenko Dmitri
• 20.05.2002

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Architectural Elements
Server
Client
Network

• The perpose of the client is to provide a user
  interface.
• The server hold resourses as programs or data.
• Servers may be mainframe computers, minicomputers
  or PC.
• The more powerfull the server th more client it
  can handle.
• The server must responds the clients requests.

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Client and server can reverse roles as needed
Transaction 1
a
b
Client
Server/Client
network
Transaction 2
c
Server/Client
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Components of the an information system
architecture

• Some of the most important components of an
  information System architecture are
• User Interface
• Data management
• Computation

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User Interface

• Sometimes it called front end.
• It consist of a keyboard, a video display and a
  mouse.
• There are three main user interface technologies
  are used today
• Dumb terminal
• X terminal
• PCs

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Dumb terminal

• The early dumb terminals keyboard and monochrom
  text only display.
• Keyboard imput/Text based output.
• Dumb terminal was user unfrendly.

X- Terminals
Such as in Unix systems. Keyboard and mouse
input/Text or graphical output.
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Data Management

• Three main data management technologies are used
  today
• Flat Files
• Relational Databases
• Object-oriented databases

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Flat Files

• Characteristics
• Lack data independence.
• Lack data sharing.
• Lack standard language.

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Relational Databases

• Characteristics
• Provide data independence.
• Provide data sharing.
• Provide standard language (SQL).

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Object-oriented databases

• Characteristics
• Provide data independence.
• Provide data sharing.
• Provide elaborate support for objects.
• Not yet standardized by international recognized
  standards body.

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Traditional Architectures

• There are two traditional Architectures
• Mainframe Architecture (1960)
• File Server Architecture (1980)

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Mainframe Architecture
Mainframe Server
Dumb Terminal
Dumb Terminal
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Characteristics of Mainframe Architecture
Component
Characteristic

• Server hardware Mainframe computer or
  minicomputer
• Client hardware Dumb terminals
• User interface Keyboard input, text output
• Data management Flat files
• Computation management COBOL programs
  (non-portable) executed on server
• Cost Medium or high
• Reliability High
• Security High
• Scalability High
• Flexibility Low

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File-Server Architecture
Pc or Minicomputer Server
Desktop PC
Desktop PC
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Characteristics of File-Server Architecture
Component
Characteristic

• Server hardware PC
• Client hardware PCs
• User interface Keyboard input, text output
• Data management Flat files
• Computation management Programs Written in
  various languages (BASIC or dBase)
  executed on client
• Cost Low
• Reliability Low
• Security Low
• Scalability Low
• Flexibility Low

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Client/Server Architecture
Pc Minicomputer or Mainframe Server
Desktop PC
Desktop PC
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Characteristics of Client/Server Architecture
Component
Characteristic

• Server hardware PC, minicomputer, or mainframe
• Client hardware PC
• User interface Graphical
• Data management Relational database
• Computation management Programs Written in
  various languages executed on server
  or client
• Cost Low to medium
• Reliability High
• Security High
• Scalability High
• Flexibility High

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Web-Server-Based Architecture
Web Server
Web Browser
Web Browser
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Characteristics of Web Server Architecture

• This is a particular form of Client-Server
  Architecture.
• Web server act as Server.
• Web browser act as Client.

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Three-Tier Architecture
Server
Server
Middleware Server
Desktop PC
Desktop PC
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Characteristics of Three-Tier Architecture

• Client can access to the Middleware server
  through a thin driver.

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Distributed Architecture
Desktop PC
Desktop PC
Desktop PC
Desktop PC
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Characteristics of Distributed Architecture

• Distributed architecture includes multiple
  servers.
• Every host potentially acts as both client and
  server. (Point to point architecture)

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Characteristics of Distributed Architecture
Component
Characteristic

• Server hardware PC, minicomputer, or mainframe
• Client hardware PC
• User interface Graphical
• Data management Relational database
• Computation management Programs Written in
  various languages executed on server
  or client
• Cost Medium
• Reliability High
• Security High
• Scalability High
• Flexibility High

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Security

• It has three components
• Confidentiality Protection against disclosure
  to unauthorized individuals.
• Integrity Protection against alteration or
  corrupting.
• Availability Protection against interference
  with the means to access the recources.

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Security

• Two security challenges have not been fully met
• Denial of service attacks.
• Security of mobile code.

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Denial of service attacks(DoS)

• DoS attacks are typically executed using DoS
  tools that send many request packets to a
  targeted Internet server (usually Web, FTP, or
  Mail server), which floods the server's
  resources, making the system unusable.

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Summary

• There are a lot of Information systems
  architectures that are used today.I have
  introduce you the main of them.