Method and apparatus for operating a computer network

A method of storing a data file in a computer network, the method comprising the steps of:

• identifying a predetermined number of computers within a computer network which satisfy one or more specified conditions by:
• a first computer which has a copy of the data file to be stored communicating to one or more of the other computers in the network a request message which includes said one or more specified conditions and a token value which is indicative of a number of computer devices to be located by the message;
• each subsequent computer which receives a request message processing the message by performing the following steps:
• determining if it is able to satisfy the one or more conditions specified in the request message and if so, reporting this fact back to the first computer and decrementing the token value within the message, and then determining if the token value in the request message indicates that at least one further computer device requires locating by the message and if so, forwarding the message, or a plurality of daughter messages, on to a subsequent computer device or devices within the computer network unless a restriction criterion has been met;
• generating a first plurality, corresponding to the identified predetermined number of computers, of erasure coded fragments from the data file such that any subset of the fragments which contains at least a smaller predetermined number of the first plurality of fragments can be used to recreate the data file;
• and
• transmitting each of the erasure coded fragments to a respective one of the identified computers for storage thereon;
• wherein at least one of the one or more specified conditions is that the computer has sufficient storage space available for storing one of said fragments.

A computer network comprising a plurality of computer devices having data connections such that each computer device within the network can communicate with any other device within the network provided both computers are running and correctly connected into the network, each device within the network comprising:

• a request generator for generating request messages each of which includes a token value indicative of the number of other devices within the network to be identified by the message and one or more specified conditions which each identified computer is to satisfy;
• and
• a request processor for processing received request messages by:
• determining if it is able to satisfy the one or more conditions specified in the request message and if so, decrementing the token value within the message and identifying itself to the originator of the corresponding received request message, and then,
• determining if the token value in the request message indicates that at least one further computer device requires locating by the message and if so, forwarding the message, or a plurality of daughter messages, on to a subsequent computer device or devices within the computer network unless a restriction criterion has been met.

A computer device for forming part of a computer network comprising a plurality of computer devices having data connections such that each computer device within the network can communicate with any other device within the network provided both computers are running and correctly connected into the network, the device comprising:

• a request generator for generating request messages each of which includes a token value indicative of the number of other devices within the network to be identified by the message and one or more specified conditions which each identified computer is to satisfy;
• and
• a request processor for processing received request messages by:
• determining if it is able to satisfy the one or more conditions specified in the request message and if so, decrementing the token value within the message and identifying itself to the originator of the corresponding received request message, and then,
• determining if the token value in the request message indicates that at least one further computer device requires locating by the message and if so, forwarding the message, or a plurality of daughter messages, on to a subsequent computer device or devices within the computer network unless a restriction criterion has been met.