Approved uniformity issues

The Ada programming language is very rigorously standardized, and the standard explicitly excludes subsets and supersets in order to encourage portability (both of programs and programmers) . In spite of this successful standardization, the Ada language does have significant harrier s to portability. The reason for this is that the standard specifically allows implementations to var y in ways that can influence the program . Some of these differences are essential for the provision of an effective Ada system on very different underlying hardware . Other differences have no obviou s purpose and therefore act as a needless barrier to portability .