Computer network system for detecting global deadlock

Claim 1

A computer system having nodes linked together, each one of said nodes comprising: a plurality of modules accessible to each other; first detecting means for detecting a formation of a pseudo closed path formed by at least some of said plurality of modules within said node, a pseudo closed path being a waiting path formed by some of said modules, either end of the path being linked to a module of a node of the computer system outside of said node itself; check request means for sending to an adjacent node of said one node, in accordance with said first detecting means detecting the formation of the pseudo closed path at said one node, a check request for the adjacent node to check for existence of a pseudo closed path within the adjacent node itself, said request including an identification number and access sequence number of a module corresponding to a forward directional end of the pseudo closed path within the one node itself; second detecting means for detecting, responsive to a request sent from another node in said computer system, formation of the pseudo closed path within the node linked to a pseudo closed path within the other node on the basis of an identification number and access sequence number included with the request sent from the other node; transfer means for sending, in accordance with said second detecting means detecting the formation of the pseudo closed path, a request to an adjacent node to check for existence of a pseudo closed path within the adjacent node, the request including an identification number and access sequence number of a module corresponding to a forward directional end of the pseudo closed path within said one node itself and also with the identification number and access sequence number affixed to the request sent from said other node; and means for determining, responsive to a request sent from another node of said computer system, whether the request which has sent by said check request means is returned to said node itself and whether deadlock has occurred, said determining based on the identification number and access sequence affixed to the request which was sent by said check request means and on an identification number and access sequence affixed to the request sent from said another adjacent node.