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Object Access Method Enablement of DB2 Thread Restrictive Subsystems

IP.com Disclosure Number: IPCOM000106543D
Original Publication Date: 1993-Nov-01
Included in the Prior Art Database: 2005-Mar-21
Document File: 2 page(s) / 48K

Publishing Venue

IBM

Related People

Carter, RN: AUTHOR [+3]

Abstract

Object Access Method (OAM) is a component of IBM MVS/Data Facility Product (MVS/DFP). MVS/DFP is the base of the Storage Management Subsystem (SMS). OAM uses SMS to manage data and auxiliary storage, additionally OAM uses DB2 to store information regarding the management of data and auxiliary storage.

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This is the abbreviated version, containing approximately 78% of the total text.

Object Access Method Enablement of DB2 Thread Restrictive Subsystems

      Object Access Method (OAM) is a component of IBM MVS/Data
Facility Product (MVS/DFP).  MVS/DFP is the base of the Storage
Management Subsystem (SMS).  OAM uses SMS to manage data and
auxiliary storage, additionally OAM uses DB2 to store information
regarding the management of data and auxiliary storage.

      DB2 is an MVS subsystem to which other address spaces can
communicate.  The medium of communication between DB2 and other
address spaces (subsystems) is via bidirectional paths called
'Threads.'  DB2 is always multi-thread but it can link with other
subsystems that can introduce thread restrictions.  There are
subsystems that allow but one DB2 transaction thread per address
space.  This DB2 thread restriction was incompatible with OAM,
because two DB2 threads per application address space were required
for applications using OAM.

      To overcome this incompatibility, an OAM service address space
was created to isolate one of the DB2 threads.  The address space is
called OTIS (OAM Thread Isolation Support).

           Note - Please refer to the Figure.

      OTIS is initially created during MVS Master Scheduler
initialization and can be stopped and restarted by operator command.
OTIS is a multitasking subsystem that communicates with other address
spaces through service elements in common storage and via
inter-address space POSTs.  OSR (the OAM application i...