Abstract: Methods, systems, and computer program products for scheduling task-related activities are disclosed. In one example, the values of a one or more of variables on which an activity is dependent are used to determine the attainability of an activity. Information relating to the variables and/or the attainability of the activity can be recorded, or used to generate notifications and/or invitations for users.

Abstract: A distributed data processing system comprising a plurality of communicating computers including at least one message originator computer and at least one message destination computer, the message originator computer originating messages to be delivered to the message destination computer, at least one manager computer responsible of managing communications between the computers, wherein the manager computer is adapted to receive the messages originated by the originator computer and to dispatch the messages to the message destination computer, and at least one backup computer adapted to take over the role of the manager computer in case of failure thereof, wherein the backup computer is adapted to receive the messages originated by the originator computer and, in case of failure of the manager computer, to dispatch the messages to the message destination computer.