It is a collection of autonomous computer.Each and every node has different server.If one server is affected it won't reflect to the other server.

It is a group of Components which is interconnected to each other in order to share resource and computational powers.

Challenges :

Security

Heterogeneity

Consistency

Transparency

Scalability

Failure handling

Then we are discussing about architecture model and architecture patterns

It connects multiple computers via a single communication channel. Furthermore, each of these systems has its own processor and memory. Additionally, these CPUs communicate via high-speed buses or telephone lines. Individual systems that communicate via a single channel are regarded as a single entity.

Nishaanth

It is a collection of different computer to communicate and coordinate among them by sharing messages.

A distributed system is a collection of autonomous computers. It has many nodes and each nodes will have their own server so if one server is failed it will not affect the other servers.

It is a collection of independent system which are interconnected.

2.Challenges in distributed system

-hetrogenity

-openness

-security

-scalability

-failure handling

-concurrency

-transparency

3.system model

#Physical model

#architectural model

#fundamental model

A distributed system is simply any environment where multiple computers or devices are working on a variety of tasks and components, all spread across a network.

Challenges in distributed systems

1) Heterogeneity

2) openness

3) security

4) scalability

5) failure handling

6) concurrency

7) Transperency

Mobile code -> middle ware

"Concurrency -> one after another "

System model

1) physical model

2) architectural system

3) fundamental model

4) early distributed systems

3 types of physical model

1) Early ds

2) internet scale ds

3) contemporary ds

Distributed system is a collection of independent components located on different machines that share messages with each other in order to achieve common goals.

Challenges of Distributed System

1.Hetrogenity

2.openness

3.security

4.scalability

5.Failure handling

6.concurrency

7.Tansperancy

System Models of diatributed System

1.Physical Model

2.Architectural model

3.Fundamental model

challenges of distributed systems

architectural model

architectural patterns

going well

2. The Web began life at the European centre for nuclear research (CERN), Switzerland, in 1989 as a vehicle for exchanging documents between a community of physicists connected by the Internet [Berners-Lee 1999].

3. A key feature of the Web is that it provides a hypertext structure among the documents that it stores, reflecting the users’ requirement to organize their knowledge. This means that documents contain links (or hyperlinks) – references to other documents and resources that are also stored in the Web. It is fundamental to the user’s experience of the Web that when they encounter a given image or piece of text within a document, this will frequently be accompanied by links to related documents and other resources.

4. The structure of links can be arbitrarily complex and the set of resources that can be added is unlimited – the ‘web’ of links is indeed world-wide. Bush [1945] conceived of hypertextual structures over 50 years ago; it was with the development of the Internet that this idea could be manifested on a world-wide scale.

WWW can be defined as the collection of different websites around the world, containing different information shared via local servers(or computers).

Working of WWW:

The World Wide Web is based on several different technologies: Web browsers, Hypertext Markup Language (HTML) and Hypertext Transfer Protocol (HTTP).

Features of WWW:

HyperText Information System

Cross-Platform

Distributed

Open Standards and Open Source

Uses Web Browsers to provide a single interface for many services

Dynamic, Interactive and Evolving.

“Web 2.0”

It is made up of three components:

1.URL(Uniform Resource Locator)

2.HTTP(HyperText Transfer Protocol)

3.HTML(Hyper Text Markup Language)

Uses of www:

1.communication

2.calls

3.Getting the information of topic,what we want

The World Wide Web is based on several different technologies: Web browsers, Hypertext Markup Language (HTML) and Hypertext Transfer Protocol (HTTP).

Components of the Web: There are 3 components of the web:

Uniform Resource Locator (URL): serves as a system for resources on the web.

HyperText Transfer Protocol (HTTP): specifies communication of browser and server.

Hyper Text Markup Language (HTML): defines the structure, organisation and content of a webpage.

The World Wide Web is made up of three components:

1.Uniform Resource Locator (URL)

2.HyperText Transfer Protocol (HTTP)

3.Hyper Text Markup Language (HTML)

Uses of www:

1.communication

2.calls

3.getting the information what we want

publishing and accessing resources and services across the Internet. Through commonly available web browsers, users retrieve and view documents of many types, listen to audio streams and view video streams, and interact with an unlimited set of services.

Its operation is based on communication standards and document or content standards that are freely published and widely implemented.

The Web is open with respect to the types of resource that can be published

and shared on it. At its simplest, a resource on the Web is a web page or some other type of content that can be presented to the user, such as media files and documents in PDF. If somebody invents, say, a new image-storage format, then

images in this format can immediately be published on the Web. Users require a means of viewing images in this new format, but browsers are designed to accommodate new content-presentation functionality in the form of ‘helper’ applications and ‘plug-ins’.

The Web is based on three main standard technological components:

• the HyperText Markup Language (HTML), a language for specifying the contents

and layout of pages as they are displayed by web browsers;

• Uniform Resource Locators (URLs), also known as Uniform Resource Identifiers

(URIs), which identify documents and other resources stored as part of the Web;

• a client-server system architecture, with standard rules for interaction (the

HyperText Transfer Protocol – HTTP) by which browsers and other clients fetch

documents and other resources from web servers.

A Web browser is used to access web pages. Web browsers can be defined as programs which display text, data, pictures, animation and video on the Internet. Hyperlinked resources on the World Wide Web can be accessed using software interfaces provided by Web browsers. Initially, Web browsers were used only for surfing the Web but now they have become more universal. Web browsers can be used for several tasks including conducting searches, mailing, transferring files, and much more. Some of the commonly used browsers are Internet Explorer, Opera Mini, and Google Chrome. 

Features of WWW: 

• HyperText Information System 

• Cross-Platform 

• Distributed 

• Open Standards and Open Source 

• Uses Web Browsers to provide a single interface for many services 

• Dynamic, Interactive and Evolving. 

• “Web 2.0” 

• the HyperText Markup Language (HTML), a language for specifying the contents and layout of pages as they are displayed by web browsers;

• Uniform Resource Locators (URLs), also known as Uniform Resource Identifiers (URIs), which identify documents and other resources stored as part of the Web;

• a client-server system architecture, with standard rules for interaction (the HyperText Transfer Protocol – HTTP) by which browsers and other clients fetch documents and other resources from web servers.