US Patent 7100035 Status display for parallel activities

When activities are operated in parallel, and there is only one status display, an ordered list is implemented with three methods of access: insertion at the top, removal from anywhere, and read of the top item. Items kept on this list are the status codes or words for the activities that are currently in progress. When a new activity begins, its status code or word is inserted at the top of the list. Whenever an activity completes, its code or word is removed from the list regardless of its location in the list, and in such a way as to preserve the order of the remaining entries in the list. Whenever the top entry in the list changes (whether through an insertion or removal), the single status display is updated to show the new top value.