Object Manager The Object Manager (internal name Ob) is an executive subsystem that all other executive subsystems, especially system calls, must pass through to gain access to Windows NT resources—essentially making it a resource management infrastructure service.[12] The object manager is used to reduce the duplication of object resource management functionality in other executive subsystems, which could potentially lead to bugs and make development of Windows NT harder.[13] To the object manager, each resource is an object, whether that resource is a physical resource (such as a file system or peripheral) or a logical resource (such as a file).