Did you notice that z/VSE supports 4-digit device addresses ?
Ingolf24 120000DRN3 Visits (3248)
With z/VSE 4.3 we introduced 4-digit device addresses. That is you can define device addresses up to X'FFFF'. So you are no longer forced to define 3-digit device addresses for z/VSE specific configurations, which simplifies IT environments with different operating systems (Linux on System z, z/OS, z/VM).
The 4-digit device address is called physical address (pcuu) and is defined for the z/VM guest or LPAR. During the IPL process the pcuu is mapped to a 3-digit device address - the VSE address (cuu).
The mapping may be defined by the system (e.g. during initial installation) or the IPL ADD statement, e.g. "ADD 2402 AS 240,ECKD". In the example the pcuu of the ECKD device is 2402, the cuu 240.
You may display the mapping of all I/O devices with the Attention Routine command "QUERY IO,CUU=ALL" or you may use our IUI hardware configuration dialogs.
z/VSE applications, messages, commands and so on address devices by the VSE address (cuu), which range from X'000' to X'FFF'.
To each physical address there is a corresponding VSE address. If the physical address is less or equal to X'FFF', the VSE address is equal to the physical address - otherwise they are different.
Virtual tape or virtual disk and POWER dummy devices always have 3-digit device addresses.
z/VM CP commands always use physical addresses.
More information is in the z/VSE Planning book on our docu