Browse Prior Art Database

Locate Global PSM in MVS

IP.com Disclosure Number: IPCOM000102491D
Original Publication Date: 1990-Nov-01
Included in the Prior Art Database: 2005-Mar-17
Document File: 1 page(s) / 40K

Publishing Venue

IBM

Related People

Cox, D: AUTHOR [+3]

Abstract

This article describes the ability to support Global Persistent Storage Mechanism (PSM) in MVS across address spaces. Persistent Storage Mechanism is a memory management system to allow transaction programs to share data. In OfficeVision/2 (OV/2) threads from different processes can share data though Global PSM. This enables processes to retain data in memory across the creation and destruction of tasks. Persistent Storage also allows data to be kept by key rather than by address pointer. This capability is needed within OfficeVision/MVS to enable code from OV/2 to be ported to MVS.

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Locate Global PSM in MVS

       This article describes the ability to support Global
Persistent Storage Mechanism (PSM) in MVS across address spaces.
Persistent Storage Mechanism is a memory management system to allow
transaction programs to share data. In OfficeVision/2 (OV/2) threads
from different processes can share data though Global PSM. This
enables processes to retain data in memory across the creation and
destruction of tasks. Persistent Storage also allows data to be kept
by key rather than by address pointer. This capability is needed
within OfficeVision/MVS to enable code from OV/2 to be ported to MVS.

      The solution is to provide a Global Persistent Storage
Mechanism for address spaces in MVS. The Global PSM structure mimics
the structure within OV/2. The key concept which has to be recreated
within MVS is that in OS/2* there are named shared segments of
memory. OV/2 assigns a name to the segment which is the Global PSM
area. The method to accomplish this in MVS is to anchor the Global
PSM within a control block in Extended Common Storage Area (ECSA).
The control block is anchored in the Extended Control Vector Table
(ECVT). Since every address space can locate the ECVT and access the
ECSA, all address spaces that support PSM can locate the Global PSM.

      The advantage to this solution is that Global memory management
is done for OfficeVision the same way in OS/2 and MVS. Memory can be
allocated by OV applications without regard to the env...