The most obvious examples are the current process simulators from AspenTech (Aspen Plus and Aspen Hysys), Honeywell Process Solutions (UniSim Design), Process Systems Enterprise (gPROMS), COCO (AmsterChem), ProSimPlus (ProSim SA) and SimSci-ESSCOR (PRO/II). However, in a more general sense it could be said that any software that “stands by itself” and calls on or uses another Software Component is itself a PME. In practice, the distinction between a PME and a PMC is not always clear, as a PMC may call on another PMC to complete its task, and therefore seems to behave as a PME. Such a clear distinction is not necessary to understand and use the concept.