Abstract: A computer virtual memory system key-lock mechanism providing for a variety of key-lock tests and key changes depending on the type of instruction involved. This key-lock mechanism provides the opportunity for users to share use of programs and data in conjunction with the keys and locks assigned to individual users by the facility manager. The mechanism prevents unauthorized access to data and programs simultaneously present within the computer. The invention is mechanized by use of tables which record the keys and locks associated with each segment of data or code. Hardware tests each data or code segment access for compatibility between the keys and locks and causes the memory reference to be rejected if disagreement exists. The keys and locks are short digit sequences associated with the user and referenced segments.

Abstract: In this apparatus for dynamically translating virtual memory addresses to real memory addresses, a master system page table maintained in a memory associates real memory addresses with their corresponding system virtual memory addresses. This table is organized with each virtual memory address stored in it at an index location which is a smaller value formed as a predetermined function of the virtual memory address value. The translator forms the index from the virtual memory address according to the function, enters the table with it, and extracts the corresponding real memory address. In a preferred embodiment, every process (i.e., job) may reference any address in any segment of a process virtual address space, and a dedicated mechanism converts such a process virtual address reference to a system virtual memory address, which then is converted to the real memory address.