Abstract: The discovery process comprises the device (10) generating messages (112, 120 126) which together have the purpose of identifying a predetermined number of devices which satisfy a test condition included in each message. These messages are sent respectively to the on-line devices (12, 20, 26) neighbouring device (10). To ensure that no more devices than necessary are identified by the messages, each message includes a variable which is referred to as a token bucket which indicates the number of devices to be discovered by the message. Additionally, each message includes a unique identifier. When a device (12, 20 26) receives a discovery message sent from another device, it determines if it satisfies the test condition and if so it sends an acceptance message to the originating device, decrements the token bucket in the message and forwards on any remaining tokens to another neighbour. The process stops once all tokens have been disposed of in this way.

Abstract: A distributed storage network of computers is disclosed in which a determination as to whether to store a data item at a computer connected to said network is made in dependence on a policy document associated with that data item. The policy document is constructed in accordance with a Document Type Definition expressed in extensible Markup Language (XML). This provides a more flexible method of system managed storage than has hitherto been achieved.