Code on demand

In distributed computing, code on demand is a general term for any technology that sends executable software code from a server computer to a client computer upon request from the client's software.

Code on demand is a specific use of mobile code, within the field of Code mobility.

Examples

Some well-known examples for the code on demand paradigm on the web are Java applets, Adobe’s ActionScript language for the Flash player, and JavaScript: The program code lies inactive on a web server until a user (client) requests a web page that contains a link to the code using the client's web browser. Upon this request, the web page and the program are transported to the user's machine using HTTP. When the page is displayed, the code is started in the browser and executes locally, inside the user's computer until it is stopped (e.g., by the user leaving the web page).

See also

References

On-demand

On-demand may refer to:

Business

Computing and Internet

Video gaming

Television and video media

Channel 4

Channel 4 is a British public-service television broadcaster that began transmission on 2 November 1982. Although largely commercially self-funded, it is ultimately publicly owned; originally a subsidiary of the Independent Broadcasting Authority (IBA), the station is now owned and operated by Channel Four Television Corporation, a public body established in 1990, coming into operation in 1993. With the conversion of the Wenvoe transmitter group in Wales to digital on 31 March 2010, Channel 4 became a UK-wide TV channel for the first time.

The channel was established to provide a fourth television service to the United Kingdom in addition to the television licence-funded BBC's two services and the single commercial broadcasting network, ITV.

History

Conception

Before Channel 4 and S4C, Britain had three terrestrial television services: BBC1, BBC2, and ITV. The Broadcasting Act 1980 began the process of adding a fourth, and Channel 4, along with its Welsh counterpart, was formally created by an Act of Parliament in 1982. After some months of test broadcasts, it began scheduled transmissions on 2 November 1982.

All 4

All 4 is a video on demand service from Channel Four Television Corporation. The service launched on 16 November 2006 as 4oD (shorthand for 4 on Demand). The service offers a variety of programmes recently shown on Channel 4, E4, More4 or from their archives. However some programmes and movies are not available due to rights issues.

The cable and IPTV versions are operated through an appropriate set-top box whilst the internet variant can be accessed via their website. All 4 generated around 215 million long-form video views on all platforms where it is available in the first half of 2011, making Channel 4 the biggest commercial UK broadcaster in the video on-demand market during the period.

On 30 March 2015, 4oD was merged into and renamed All 4.

Web platforms

Channel4.com

All 4 is the main source of on demand programmes from Channel 4, E4, and More4. The catch up service currently lasts 30 days, and the archive has thousands of hours of programming.

As of April 2009, the internet version is fully available to Linux, Mac, and Windows users with Adobe Flash Player installed.