(1) Pertaining to a resource that is currently operational.
(2) Pertaining to a file, page, or programme that is in main storage or memory, as opposed to a file, page, or programme that must be retrieved from auxiliary storage.
(3) Pertaining to a node or device that is connected or is available for connexion to another node or device.
(4) In cross-site mirroring, pertaining to the configuration state of a mirror copy that indicates geographic mirroring is being performed.