Use of Storage Address Register for Storage Protection
Original Publication Date: 1984-Jun-01
Included in the Prior Art Database: 2005-Feb-04
This article relates to the implementation of a storage protection mechanism in a central unit with a minimum number of registers and circuits. The same register and associated hardware are used to perform the key setting and the key value comparison and checking. Various storage keys assigned to each of the main storage segments are necessary to perform the storage protect function. The following implementation of the storage protect mechanism allows the logic circuit number to be minimized by using the storage address register (SAR) for counting the various storage keys in a key random-access memory. The storage protect is a means for notifying the control program whenever the contents of the storage are accessed for an unauthorized modification or unauthorized code execution.