Introduction to the New Mainframe: z/VSE Basics

Chapter 3. z/VSE overview 77

Address space isolation

The use of address spaces allows z/VSE to maintain the distinction between the

programs and data belonging to each address space. The private areas within

one user’s address space are isolated from the private areas within other

address spaces, and this provides much of the operating system’s security.

Yet, each address space also contains a common area that is accessible to

every other address space. Because it maps all of the available addresses, an

address space includes system code and data as well as user code and data.

Thus, not all of the mapped addresses are available for user code and data.

The ability of many users to share the same resources implies the need to

protect users fro ...