1. In an automatic data processing apparatus for processing information, including a virtual memory having stored therein a plurality of different types of groups of information, each information group-type associated with an address space in said virtual memory bounded by a segment having adjustable bounds, said information being protected against unauthorized uses by a hierarchy of concentric ring levels (i.e. levels of privilege) wherein each group-type of information is associated with a predetermined ring number indicative of a level of privilege, said level of privilege decreasing as the associated ring number increases, an apparatus for generating a write-violation-exception signal comprising: (a) first means for storing first information indicating the maximum ring number RD (i.e. minimum level of privilege) required to read invormation from said selected group; (b) second means for storing second information indicating the maximum ring number WR (i.e. minimum level of privilege) required to write information into said selected group; (c) third means for storing third information indicating the maximum ring number MAXR (i.e. minimum level of privilege) required to process information from said selected group; (d) fourth means interconnecting said first, second and third means, for determining the maximum of the contents of said first, second and third means, whereby an effective address ring number EAR is generated; (e) fifth means connected with said second means, for comparing the effective address ring number EAR with the write ring number WR; and, (f) sixth means connected with said fifth means for generating a write-violation-exception signal when EAR is greater than WR.