CONTROL METHOD AND MECHANISM FOR ZERO-ORIGIN DATA SPACES

Within a data processing system, a control method and mechanism for supporting a data space without common segments in addition to traditional address spaces containing common segments. The invention includes logic for eliminating duplication of lookaside table entries for virtual addresses within shared segments, but not for identical virtual addresses within data address spaces; it also provides for overriding low address protection for store operations into data spaces. Thus, it permits the entire virtual addressing range to be available to programs wishing to use such data spaces for data isolation and data sharing.