Enterprise Systems Architecture/370: An Architecture for Multiple Virtual Space Access and Authorization

The Enterprise Systems Architecturel370" provides a significant step in the IBM System/370 evolution by providing new capabilities for virtual addressing and program linkage across multiple address spaces. This paper reviews the evolution that led to this advance and illuminates the goals, such as eliminating growth constraints and improving security, integrity, reliability, and performance, that have guided it. The major architectural capabilities are discussed, along with the system environments in which they are useful. The rationale for design choices is presented and related to issues of performance, access authorization, and constraints relief.