A logical SRB resource is a SRB Resource that is derived from Physical Resources. A logical SRB resource might be derived with further constraints on a registered physical resource or by combining more than one physical resource as an entity. For example, if a physical resource 'A' is defined using a particular directory in a HPSS, a logical resource A-bar might be defined as a resource that restricts to a further sub-directory in 'A'. A 'logical SRB resource set' is kind of logical SRB resource. It is defined as a set of physical SRB resources. The aim is for this is to give a unique (logical) name to a set of resources and when SRB opens or writes a buffer to the logical resource it opens or writes to every resource in that set. A logical resource containing multiple physical resources can be treated as a 'single' resource when using it.