Abstract: A method of creating a data structure or map describing the I/O configuration and of verifying and resolving errors in configuration data in a system in which processors are coupled to one another or to device control units either directly or through a dynamic switch by way of links attached to link adapters of respective end units. Each pair of unit link adapters coupled to the respective ends of a link exchanges information identifying the unit and the adapter on that unit. A physical configuration map indicating the actual physical system configuration is constructed from such "nearest neighbor" information. This physical configuration map is compared with a logical configuration map indicating the user-defined logical system configuration to determine the existence of any discrepancies therebetween, and one map is conformed to the other as appropriate.