The JES device information service optionally supports returning device data in 64-bit addressable virtual storage (see option SSJDPD64 in the SSJDPOPT field). A caller must be in 24 or 31-bit addressing mode when making a call to the IEFSSREQ macro. However, a caller might request that device data is returned in interface-controlled storage areas, located above the bar and only addressable through 64-bit address.

To access this data, a caller must switch to 64-bit addressing mode after the call to the IEFSSREQ macro and operate appropriately with the 64-bit pointers embedded in the data. Note that a caller running in 64-bit addressing mode can also access any data returned in 31-bit addressable storage (below the bar) using 64-bit pointers, although 64-bit mode is not required to do so.