Editing Workflow (section)

== Components ==
A workflow can usually be described using formal or informal flow diagramming techniques, showing directed flows between processing steps. Single processing steps or components of a workflow can basically be defined by three parameters:
#input description: the information, material and energy required to complete the step
#transformation rules: [[algorithm]]s which may be carried out by people or machines, or both
#output description: the information, material, and energy produced by the step and provided as input to downstream steps

Components can only be plugged together if the output of one previous (set of) component(s) is equal to the mandatory input requirements of the following component(s). Thus, the essential description of a component actually comprises only input and output that are described fully in terms of [[data type]]s and their meaning ([[semantics]]). The algorithms' or rules' descriptions need only be included when there are several alternative ways to transform one type of input into one type of output – possibly with different accuracy, speed, etc.

When the components are non-local services that are invoked remotely via a computer network, such as [[Web service]]s, additional descriptors (such as [[Quality of service|QoS]] and [[availability]]) also must be considered.<ref>{{cite journal | author = D. Kyriazis| title = An innovative workflow mapping mechanism for Grids in the frame of Quality of Service | journal = Future Generation Computer Systems | volume = 24 | issue = 6 | pages = 498–511 | date = June 2008 | doi = 10.1016/j.future.2007.07.009|display-authors=etal}}</ref>