Portability enables interactive courseware (ICW) and associated application programs to operate on computer-based systems other than the ones on which they are developed. Courseware portability will increase sharing of ICW across a range of instructional settings within military services and across internationally allied military services. The Department of Defense (DoD) had advocated and implemented a standard for ICW development employing a virtual device interface that currently incorporates specified commands organized into service groups for system management, visual management, videodisc control, and XY-input devices. This approach, now specified in some DoD instructions, provides for system-level courseware portability. Future work will expand the standard to: (1) encompass more varieties of ICW; (2) address portability at the device level; (3) address new technological opportunities; (4) better address graphics; (5) encompass more operating systems; and (6) progress from platform independence to authoring software independence. The DoD portability initiative will lower the per-unit costs of ICW, lower instructional system development costs, increase use of advanced instructional technology in military settings, and increase instructional efficiency in the military services. Four flowcharts and one table illustrate the discussion. (Contains 18 references.) (Author/SLD)