Storage protect key array for a multiprocessing system

Claim 1

In a multiprocessing system with a data storage hierarchy, a plurality of processors for processing data, a main memory connected to each of said plurality of processors and divided into a plurality of storage protect areas, a plurality of storage protect keys each of which is associated with one of said storage protect areas in main memory, and a plurality of apparatuses for retaining storage protect keys, wherein each said apparatus is connected to a corresponding one of said processors, and wherein each said apparatus comprises: address receiving means connected to its corresponding processor for receiving addresses of data desired and instructions; local high speed storage means connected to said main memory for retaining blocks of data stored in said main memory; key array means connected to said address receiving means for retaining an entry for each of said blocks of data retained in said local storage means, each entry containing (a) the storage protect key corresponding to that block of data retained in said local storage means, and (b) a portion of the address corresponding to that block of data retained in said local storage means; comparison means connected to said address receiving means and said key array means for comparing the portion of address in the key array entry with the corresponding portion of the address in said address receiving means; and means for accessing said key array means and said address receiving means to determine by the aforesaid comparing function whether the storage protect key associated with the data represented by the address in said address receiving means, is resident in said key array means.