Browse Prior Art Database

Extended Storage Capability

IP.com Disclosure Number: IPCOM000083937D
Original Publication Date: 1975-Aug-01
Included in the Prior Art Database: 2005-Mar-01
Document File: 2 page(s) / 14K

Publishing Venue

IBM

Related People

Mall, M: AUTHOR [+2]

Abstract

Introduction: The addressing capacity within a single multiple virtual storage (MVS) address space can be a limiting factor under some circumstances. Specifically, a requirement existed to provide a simulated storage capacity of up to 200 megabytes within a single MVS address space. The following is a description of a technique using existing MVS facilities which provides such an extended storage capability.

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Extended Storage Capability

Introduction: The addressing capacity within a single multiple virtual storage (MVS) address space can be a limiting factor under some circumstances. Specifically, a requirement existed to provide a simulated storage capacity of up to 200 megabytes within a single MVS address space. The following is a description of a technique using existing MVS facilities which provides such an extended storage capability.

Overview. The concept of this extended storage capability is similar to the V/O support in MVS. That is, a "large" (greater than 16 megabytes) data space is created in auxiliary storage and is made virtually addressable to the user through a "window" as required. The existing auxiliary storage management (ASM) functions (Assign, Release) are used to allocate/ deallocate the virtual data set in the paging hierarchy. Existing real storage management functions to make auxiliary pages addressable (assign) and to remove addressability and place data in the auxiliary space (move out) are also used.

Once validated in the window (see XLATE interface below) the data is accessed via the normal MVS paging system. Hence, the total size of the data space is only limited by the virtual data set capacity, and the total actual addressability at any one point in time is limited only by the "window" size. The limit of the window size is a function of the space available in the MVS private address space.

Structure. The storage manager to provide the described capability consists of three functional parts: initialization/termination; auxiliary management; and window management.

The initialization function (see Init Interface below) is called by the extended storage manager user to construct required tables, and to invoke the MVS auxiliary storage manager to allocate an auxiliary data set. Termination is invoked conversely to release the data set and free table space. Auxiliary management performs three basic functions. First, it must allocate ("create") an object in the data space and assign it an identifier; second, it must deallocate (see destroy) the object and release i...