Programmable Masking for Protection Keys
Original Publication Date: 1988-Dec-01
Included in the Prior Art Database: 2005-Feb-15
This article describes a technique to assure protection while providing for access to a storage block associated with a storage controller wherein a key is associated with each block. Input/output (I/O) devices must present a key selector to the storage controller so that access authority can be determined. The verification of storage access by key comparison prevents both intentional and inadvertent unauthorized storage access. When an I/O device wishes to read or write data to storage or another I/O device, a command, an address, a storage block key, and possibly data are transmitted. The storage block key that the I/O device presents must match the key that the storage controller obtains for the access to be allowed.