Distributed back up of data on a network

The present invention relates in general to data processing systems, and in particular, to the backing up of data within a network of data processing systems. Within a network of computers, a system administrator function controls the backing up of data of client machines to selected other client machines within the network by removing control of and access to portions of the hard files within those machines to the local user. The freed up storage space within the client's local hard files is then used for backup purposes to backup data from other machines within the network. Agents in the server and client machines perform this task making it possible to distribute the backup workload across the network. There are three modes of backup: source initiated, target initiated, and server communal backup (CB) agent initiated. All are coordinated by the server CB agent.