a web service that provides atomic advisory locking would be pretty easy to write.
For that matter so would a datagram service, and that would be more efficient. Requests would include: resource-ID-string a character string uniquely identifying what is getting locked lock-disposition SHARED, EXCLUSIVE, or UN. All requests are nonblocking. request-identifier a character string uniquely identifying this request, for robustness timeout how many seconds to wait before calling this lock stale and breaking it Responses would include: request-identifier copied from request result (lock-disposition) GRANTED or FAILED Security would be based on peer IP address, with the server throwing away requests from unlisted peers (amounting to the same thing as a firewall rule) Use a VPN to encrypt all traffic if you want, rather than adding encryption features to the remote resource locking protocol. Have I just described something that already exists? -- david nicol "Take your time." -- Allan Quaterman