Managing Digital Files with Shared Locks

A computer program product comprising a non-transitory computer usable medium having a computer readable code embodied therein for controlling a data processing apparatus, the computer readable program code configured to cause the data processing apparatus to execute a process for managing the access and use of digital files stored in a file storage networked with multiple servers, the process comprising the steps of:

• (a) a requesting server among the multiple servers that desires to access and use a file stored in the file storage sending to the other servers of the multiple servers a query containing an identification (ID) of the file;
• (b) each of the other servers receiving the query checking an internal lock list to ascertain whether the file ID is listed therein,
• (b)(i) if listed then returning a failure message to the requesting server;
• (b)(ii) if not listed then returning a success message to the requesting server;
• (c) the requesting server determining from all returning messages whether a failure message exists,
• (c)(i) if exists then not to access and use the file, and sending repeated queries at a predetermined time interval;
• and
• (c)(ii) if not exist then access and use the file, and sending a notice to all other servers when finishing using the file.