Computer Aided Scheduling System (COMPASS) is a generic, nonchronological, interactive scheduler. It is generic in the sense that it can be applied to any problem where activities are placed on a timeline while respecting a variety of constraints, including resource, temporal, and state constraints. It is non-chronological in the sense that schedules are built incrementally by placing activities on the timeline one-at-atime and that the sequence in which activities are placed on the timeline is not constrained by their order in time. High priority activities and those that are time constrained can be placed on the timeline first, even though they may be scheduled to occur later in time than other low priority activities. In non-chronological scheduling systems, an activity is placed on the timeline in roughly four steps:

1. compute the intervals of time where all of its requirements and constraints are satisfied,
2. select one of these intervals,
3. align the activity within the selected interval, and
4. post reservations against the required resources during the chosen interval.

COMPASS employs a general algorithm which computes the set of all satisfying intervals. This enables the system, or the interactive user, to employ sophisticated preference functions to choose the "best" interval and to align the activity at the "best" location in the chosen interval.

COMPASS allows the user to build schedules one activity at a time or to build schedules using automated methods. Once the schedule is created, the user may move the activities around, change resources or requirements, or create multiple schedules to reflect various scenarios. COMPASS ensures that constraints are not violated while the user manipulates the schedule. This allows the user to focus on the quality and overall look of the schedule while COMPASS maintains the schedule's validity.