Abstract: A power control system for workstations (31-54) which are connected to a network (2). An application (300) running on a server (1) has access to a profile database (304) which stores records of estimated workstation start and end times and estimated user start and end times, and sends shut down and start up instructions to each workstation in accordance with the profile data. The time assumed to be the working day start for a workstation is either the estimated working day start for that workstation, or the estimated working day start for the user most likely to use that workstation. The time assumed to be the working day end for a workstation is either the estimated working day end for that workstation, or the estimated working day end for a user on that workstation. Workstation and user data is logged (303) to create the profiles.

Abstract: A data processing system for distributing a package of data from a source to a plurality of data processing machines arranged in a plurality of sites. The data is transmitted from the source to the plurality of data processing machines by means of a multicast. At each site, a local data processing machine is designated as a site master; the other local data processing machines report missing data portions to the site master; and the site master consolidates reports of missing data portions, and requests missing data portions from the source. The source then transmits the missing data portions to the plurality of data processing machines by means of a further multicast. If the site master receives a report of missing data that the site master has stored locally, the site master provides that missing data to the local machines by means of a site multicast.