Types of Pipelines:

Instructional pipeline

 It is used where different stages of an instruction fetch and execution take place in a pipeline.

Arithmetic pipeline

 It is used where different stages of an arithmetic operation take place along the stages of a pipeline.

The definitions are right but are based on a narrow perspective, assume only the central processor. There is other type of computing pipelines. Pipelines are used to compress data and transfer video data. Another is to use of specialized hardware to perform graphics display tasks. According to Ware Myers:

"...the pipeline concept ... transforms a model of some object into representations that in succession become more machine-dependent and lastly results in an image upon a specific screen.

This instance of pipelining fits the definitions from Hayes and Chen but not the from Tabaz. These broader categories are beyond the scope of this paper and are specified only to alert the reader that different authors mean different things when referring to pipelining.