HOST=x

Identifies this DFSMShsm host in an HSMplex. The HOST=x keyword specifies a unique identifier for each instance of DFSMShsm. For x, substitute the host identification as an upper-case alphabetic character from A to Z, a digit from 0 to 9, or the character @, #, or $.

Note:

The earlier definition of the HOST= keyword allowed an optional second character in the value. The function of that second character is now specified by the PRIMARY= keyword. The second character, if specified, is considered only if the PRIMARY= keyword is not specified.
DFSMShsm supports the use of @, #, and $ as host identifier characters that may show up in dataset names and TSO output. You are not required to use them and, (especially if you are a non-US customer) you may choose to limit yourself to characters A-Z, and 0-9, reducing the total number of host address spaces per HSMplex to 36 instead of 39.