The installation's device groups are defined in the eligible device table (EDT). An EDT is an installation-defined and named representation of the devices that are eligible for allocation. This table also defines the relationship of generic device types and esoteric group names. The term “generic device type” refers to the general identifier IBM® gives a device; for example, 3380. An esoteric device group is an installation-defined and named collection of I/O devices; TAPE is an example of an esoteric group name. See z/OS HCD Planning for further information on the EDT.