Differences between internet,intranet and extranet

How does one distinguish between an intranet and an extranet? When I access company-only information over the Internet, is that an intranet or an extranet?
A: The term "intranet" is somewhat misleading conceptually, because it invites a contrast to the term "Internet." The real contrast is with the World Wide Web--an important distinction, because "Internet" focuses on physical and technical networks, while the Web focuses on the set of content accessible on that physical and technical infrastructure.
When I coined the term "IntraNet" at Amdahl Corp. in the summer of 1994, it did have the connotation of an internal Web rather than just an internal Internet. In fact, the term we used internally before this was the too-cumbersome "Enterprise-Wide Web." So, while the ambiguity of "intranet" was apparent even back then, for lack of a better alternative, it caught on.
In the early days, I defined an intranet as "An infrastructure based on Internet standards and technologies that supports sharing of content within a limited and well-defined group." The "infrastructure" referred to the organizational and management infrastructure that created, managed, and shared the content. The only technical constraint was that the physical network be based on the Internetworking Protocol (IP).
You might notice that this definition encompasses what we call extranets today, because the defining factor is a "limited and well-defined group," and does not specify any official organizational affiliation. The Web, in contrast, is an unlimited group.
Today I think of intranets, extranets, and the Web as collections of content. An intranet is a set of content shared by a well-defined group within a single organization. An extranet is a set of content shared by a well-defined group, but one that crosses enterprise boundaries.
These access distinctions are important, because Web-based content uses the same technical infrastructure regardless of access decisions. This means it is much easier to change access to specific content than it was in the old proprietary world,where making something more widely available often entailed a major conversion effort.
As technical infrastructure becomes less of a barrier to accessing specific content, it becomes important to pay attention to how, or if, we want to restrict access. The terms "intranet" and "extranet," as imperfect as they are, provide us with conceptual and pragmatic tools for discussing to whom we want to make specific content available.
These terms may continue to evolve in meaning. For now, a set of content accessed by members of a single organization is an intranet, even if the information travels across the public Internet infrastructure.

Type of computer

A computer is a programmable machine that receives input, stores and manipulates data, and provides output in a useful format.
Although mechanical examples of computers have existed through much of recorded human history, the first electronic computers were developed in the mid-20th century (1940–1945). These were the size of a large room, consuming as much power as several hundred modern personal computers (PCs).[1] Modern computers based on integrated circuits are millions to billions of times more capable than the early machines, and occupy a fraction of the space.[2] Simple computers are small enough to fit into small pocket devices, and can be powered by a small battery. Personal computers in their various forms are icons of the Information Age and are what most people think of as "computers". However, the embedded computers found in many devices from MP3 players to fighter aircraft and from toys to industrial robots are the most numerous.
The ability to store and execute lists of instructions called programs makes computers extremely versatile, distinguishing them from calculators. The Church–Turing thesis is a mathematical statement of this versatility: any computer with a certain minimum capability is, in principle, capable of performing the same tasks that any other computer can perform. Therefore computers ranging from a netbook to a supercomputer are all able to perform the same computational tasks, given enough time and storage capacity.

characteristics multimedia

Major characteristics of multimedia
Multimedia presentations may be viewed in person on stage, projected, transmitted, or played locally with a media player. A broadcast may be a live or recorded multimedia presentation. Broadcasts and recordings can be either analog or digital electronic media technology. Digital online multimedia may be downloaded or streamed. Streaming multimedia may be live or on-demand.
Multimedia games and simulations may be used in a physical environment with special effects, with multiple users in an online network, or locally with an offline computer, game system, or simulator.
The various formats of technological or digital multimedia may be intended to enhance the users' experience, for example to make it easier and faster to convey information. Or in entertainment or art, to transcend everyday experience.

A lasershow is a live multimedia performance.
Enhanced levels of interactivity are made possible by combining multiple forms of media content. Online multimedia is increasingly becoming object-oriented and data-driven, enabling applications with collaborative end-user innovation and personalization on multiple forms of content over time. Examples of these range from multiple forms of content on Web sites like photo galleries with both images (pictures) and title (text) user-updated, to simulations whose co-efficients, events, illustrations, animations or videos are modifiable, allowing the multimedia "experience" to be altered without reprogramming. In addition to seeing and hearing, Haptic technology enables virtual objects to be felt. Emerging technology involving illusions of taste and smell may also enhance the multimedia experience.
[edit] Terminology

CategorizAtion of Multimedia

Multimedia may be broadly divided into linear and non-linear categories. Linear active content progresses without any navigational control for the viewer such as a cinema presentation. Non-linear content offers user interactivity to control progress as used with a computer game or used in self-paced computer based training. Hypermedia is an example of non-linear content.
Multimedia presentations can be live or recorded. A recorded presentation may allow interactivity via a navigation system. A live multimedia presentation may allow interactivity via an interaction with the presenter or performer.

Multimedia

Multimedia is media and content that uses a combination of different content forms. The term can be used as a noun (a medium with multiple content forms) or as an adjective describing a medium as having multiple content forms. The term is used in contrast to media which only use traditional forms of printed or hand-produced material. Multimedia includes a combination of text, audio, still images, animation, video, and interactivity content forms.
Multimedia is usually recorded and played, displayed or accessed by information content processing devices, such as computerized and electronic devices, but can also be part of a live performance. Multimedia (as an adjective) also describes electronic media devices used to store and experience multimedia content. Multimedia is distinguished from mixed media in fine art; by including audio, for example, it has a broader scope. The term "rich media" is synonymous for interactive multimedia. Hypermedia can be considered one particular multimedia application.

Examples of individual content forms combined in multimedia:



Text
Audio
Still Images



Animation
Video Footage
Interactivity