Real Storage Operand Facility
Original Publication Date: 1985-Jan-01
Included in the Prior Art Database: 2005-Feb-18
The Dynamic Address Translation (DAT) facility in an IBM System/370 control processing unit (CPU) provides a mechanism for instructions and data to reside in virtual storage whereby the DAT facility translates a program's virtual addresses into real storage addresses. However, there are times when a program, particularly the system control program, must reference storage with real addresses. Many tables and structures have been provided which require real addresses to be accessed. For example, segment tables may be accessed by the control program using real addresses. The direct referencing of real addresses in System/370 requires the CPU to run with DAT turned off.