Hierarchial memory ring protection system using comparisons of requested and previously accessed addresses

摘要

A data processing system handles thirty-two bit logical addresses which can be derived from either sixteen bit logical addresses or thirty-two bit logical addresses. The system uses hierarchical memory storage using in a particular embodiment eight storage segments (rings), access to the rings being controlled in a privileged manner according to different levels of privilege. The segment locations are designated by successive segment numbers having a descending order of protection with reference to data accesses thereto. A current address for data access includes a segment identification and a comparison is made with the segment identification of a preceding address to determine whether access can be made by the current address.