WEB DEVELOPMENT CONCEPTS 1.

  Understanding the Layers:

Presentation Layer :

The presentation layer is responsible for the following:
  • Data encryption/decryption
  • Character/string conversion
  • Data compression
  • Graphic handling  
 The presentation layer mainly translates data between the application layer and the network format.


Application Layer:

The application layer provides many services, including:
  • Simple Mail Transfer Protocol
  • File transfer
  • Web surfing
  • Web chat
  • Email clients
  • Network data sharing
  • Virtual terminals
  • Various file and data operations
The application layer provides full end-user access to a variety of shared network services for efficient OSI model data flow.

 Related image

Resource Management Layer:

On top of the hardware layer, the resource management layer is responsible for both sharing of hardware resources and the enforcement of mandatory access control rules based on the available hardware resources.



Web System Architecture 

There are three main types of web architecture :
1.One-Tier
2.Two-Tier
3.Three-Tier

One-Tier Architecture: 
In this type of architecture all the information  resides at the same program. It is called as the stand-alone architecture.

Two-Tier Architecture:
It is a typical client-server architecture. The presentation layer is isolated at the client side , while the rest of the two layers are managed by the server side. 

Three-Tier Architecture:
The three layers , Presentation, Application, and Resource management are managed independently on different modules. 


URL & Domain

URL, (Uniform resource locator) is a path towards the designated site. For example 
"https://www.blogger.com/blogger.g?rinli=1&pli=1&blogID=1910797663783620384#editor/target=post;postID=8918188452917822447" 
is the URL to this blog.

It becomes quiet tedious to remember such paths. 

Domain Name is the name that you own on the internet and you basically register with a domain registrar.  For example "Blogspot.com" or "Google.com".


Cross Browser Compatibility

When every site is coded, it has to be tested in various browsers. All browsers tend to give different results for the same HTML+CSS code. Radio buttons might work on FireFox but not on Internet Explorer. 
Chrome yellow may seem to be darker on Google Chrome, and lighter on Safari. 

This incompatibility of the code with different browsers is called as Cross Browser Compatibility. 




 

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