International Business Machines Corporation

Eugene S Schulze

Richard J Schmalz

Kenneth G Rubsam

Casper A Scalzi

Catherine Krueger Eilert

Danny R Sutherland

Donald H Gibson

David C Manners

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.

System for designating real main storage addresses in instructions while

A non-main storage data space (NMDS) is presented, whose virtual pages may be backed by expanded storage, by a combination of expanded and auxiliary storage, but not by main storage. Mechanisms are provided to prevent direct referencing of data in a NMDS by instructions, and to bring data into and out of NMDS's. The I/O mechanisms minimize physical I/O by exchanging pointers to backing pages in appropriate cases. Additionally, control is returned immediately to I/O-initiating applications, when I/O is required between an address space and a NMDS, without the need for synchronization by the application: the mechanism provides for synchronization by the system's page fault processing.

Method and system for storing data in and retrieving data from a

A linear data set is mapped to one or more non-main storage virtual data spaces. Portions of this data space are then selectively mapped to a 'window' in an address space in which an application is executing, and changes made in this 'window' are temporarily saved in the data space. After completion of processing, the application may permanently save changed data from the data space to the linear data set. The technique for mapping the data space to the address space may be used to map between two address spaces, and may be extended to encompass third and subsequent spaces, so that a reference to a mapped address in the first space will ultimately be interpreted as a reference to an address in the last mapped space.

Method and system for performing virtual address range mapping in a

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Wappingers Falls, NY, United States of America

Eugene S Schulze