Platform Independent Model (PIM) is a model of a subsystem that contains no information specific to the platform or the technology that is used to realize it. The quality that the model is independent of the features of a platform of any particular type. Like most qualities, platform independence is a matter of degree. A view of a system from the platform independent viewpoint. A PIM exhibits a specified degree of platform independence so as to be suitable for use with a number of different platforms of similar type. [MDA Guide]. Platform Independent Viewpoint: Focuses on the operation of a system while hiding the details necessary for a particular platform. A platform independent view shows that part of the complete specification that does not change from one platform to another
Source: Platform-Independent Model (PIM)