Strategies for supporting application portability

A range of system-design strategies that can be used to support portability and the ways in which these strategies have been employed by past and present systems are examined. The strategies are grouped into three categories: (1) strategies that maintain identical execution-time interfaces by porting system components that form the interface, (2) strategies that maintain identical or nearly identical interfaces for different system components by adhering to appropriate standards, and (3) strategies that assist in the adaptation of programs to a target environment. The principal emphasis is on operating-system issues. User interface portability, dynamic portability in a network, and international exchange of programs are briefly considered.<>