Graceful degradation

With Graceful degradation (d .: graceful degradation) directional stability and safety reaction is called a (computer) system for errors, unexpected events or partial failures of the system, in which the (computer) system maintains operation as far as possible . A fault in a subsystem only reduces the functionality of the overall system gradually, for example through lower quality or fewer functions.

For example, the Transmission Control Protocol (TCP) is structured in such a way that it allows reliable two-way communication in a packet-based network , even if individual nodes in the network are overloaded, incorrectly configured or corrupted data. This is achieved by the communication endpoints reacting accordingly if packets are lost, duplicated, rearranged or falsified.

Graceful degradation for websites

Also, data formats can be designed in terms of a "graceful degradation". For example, HTML is built upwardly compatible , new HTML units are ignored by browsers that do not know these HTML units, and the rest of the document is displayed anyway. Examples:

Instead of an image that cannot be displayed, alternative text is displayed.
With the appropriate implementation of the HTML page, images can be displayed as a substitute for Flash films.
JavaScript can be written to replace DOM operations with page reloads.
HTML5 input elements of the type "range" or "email" are displayed by older browsers as normal text elements, without additional functionality.

literature

Andrea Ertel, Kai Laborenz: Responsive web design - programming and designing adaptable websites. 2nd Edition. Galileo Computing (now Rheinwerk Verlag), Bonn, 2015, ISBN 978-3-8362-3200-5

Web links

Graceful degradation , defined on the sides of the TechTarget network ( Engl. )
Graceful degradation , definition on about.com ( Engl. )

Individual evidence

↑ Andrea Ertel, Kai Laborenz: Responsive Web Design - Programming and designing adaptable websites . 2nd Edition. Galileo Computing (now Rheinwerk Verlag), Bonn 2015, ISBN 978-3-8362-3200-5 , p. 29-32, 75, 170 ff .
↑ graceful degradation. In: "Spektrum.de": Lexicon of Neurosciences. Spektrum Akademischer Verlag, 2000, accessed on February 26, 2016 : “graceful degradation [E], the gradual (not abrupt) decline in the performance of information processing systems with a gradual reduction in resources such as computing power, time and capacity. [...] "

[:0-1] Andrea Ertel, Kai Laborenz: Responsive Web Design - Programming and designing adaptable websites . 2nd Edition. Galileo Computing (now Rheinwerk Verlag), Bonn 2015, ISBN 978-3-8362-3200-5 , p. 29-32, 75, 170 ff .

[2] graceful degradation. In: "Spektrum.de": Lexicon of Neurosciences. Spektrum Akademischer Verlag, 2000, accessed on February 26, 2016 : “graceful degradation [E], the gradual (not abrupt) decline in the performance of information processing systems with a gradual reduction in resources such as computing power, time and capacity. [...] "