Return unit name - Function code 2
This function returns the unit name associated with a look-up value provided as input. The unit name is the EBCDIC representation of the IBM® generic device type (for example, 3390) or the esoteric group name (for example, TAPE) from the EDT.
A look-up value is an internal representation of the unit name, used as an index into the EDT. Because teleprocessing devices do not have generic device names, you cannot use this function to request information about teleprocessing devices.
Note: Do not use this function to determine whether a returned
unit name is a generic CTC device or an esoteric group name that contains
CTC devices. Instead, use the return attributes function (function
code 8) for this purpose.