File extension by clients in a distributed data processing system

摘要

The system and method of this invention controls how client data processing systems in a distributed networking environment can efficiently extend files and write into regions of the files previously unoccupied by data. The server data processing system manages the distributed allocation of new file blocks by sending nascent zeros in addition to real bytes that have been requested by the client data processing system. Nascent zeros are logically zero bytes that have never been stored to or written to, and may be outside the current extent of the file. The server determines whether or not this additional range of nascent zeros will be sent to a client depending upon the amount of physical storage available at the server, and whether or not other client data processing systems require access to this range of blocks. Likewise, the client data processing system has the option of writing to this additional range of nascent zeros. By writing to the additional range of nascent zeros, a client data processing system can minimize the network traffic overhead used in sending messages to the server data processing system requesting a range of bytes.