Abstract: A LOCK PAGE instruction is provided for locking a page of real storage using a virtual address. The LOCK PAGE instruction includes an operation code which specifies the operation to be performed, a first operand which contains the value of the real address obtained during execution of the LOCK PAGE instruction and a second operand which contains the value of the virtual address of the page to be locked during execution of LOCK PAGE. LOCK PAGE enables an address page or a data page to be locked without requiring the entire address space to be locked. A page is locked when a lock control bit in general register 0 is zero, the page is valid in main storage and a lock bit located in a page table entry is zero. In addition to the above, the technique used by an operating system service for reclaiming a page of real storage is altered to intersect with the LOCK PAGE facility.

Abstract: A data processing system includes central storage where access to data is by central storage addresses. Instructions normally include a logical or virtual address which is translated to a real central storage address using dynamic address translation (DAT) with or without an access register (AR) translation mechanism. When in AR mode, and with DAT on, addressing of instructions or data in central storage can be effected by specifying real central storage addresses and eliminate the DAT and AR translating process.