Browse Prior Art Database

Session Management in a Data Access System

IP.com Disclosure Number: IPCOM000035675D
Original Publication Date: 1989-Jul-01
Included in the Prior Art Database: 2005-Jan-28
Document File: 5 page(s) / 77K

Publishing Venue

IBM

Related People

Bennett, RB: AUTHOR [+2]

Abstract

The Session Management System is described as part of a Data Access System, which is a component of a File Access Processor. A File Access Processor and its other components, the Service System and the Storage Access System, are not included in this disclosure. Likewise, the other components of the Data Access System: Space Management, Catalog Management, and Request Management are not described in detail. The File Access Processor processes requests for data access from a set of Application Support Processors which share a set of data file resources.

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Session Management in a Data Access System

The Session Management System is described as part of a Data Access System, which is a component of a File Access Processor. A File Access Processor and its other components, the Service System and the Storage Access System, are not included in this disclosure. Likewise, the other components of the Data Access System: Space Management, Catalog Management, and Request Management are not described in detail. The File Access Processor processes requests for data access from a set of Application Support Processors which share a set of data file resources.

Disclosed is the routing and control function for the Data Access System. Session Management supports Data Access System initialization, request routing, completion of work unit processing, deferred work unit commits, response buffer management, and termination processing. A number of routines are included in the operation of Session Management. Some of these routines are also utilized by other subcomponents of the Data Access System as common services. Following are the Session Management routines: o The Terminate Routine manages the clean up of storage and control structures when service to a particular Application Support Processor is ended. Terminations occur from implicit failures (communications failures between an Application Support Processor and a File Access Processor, deadlock on resources, etc.) and explicit actions (system operator forced, Application Support Processor ended, etc.). Terminations are discovered upon initial entry into Session Management or at any other point when an activation of the Data Access System regains control after an invocation of either the Service System or the Storage Access System. Therefore, the Terminate Routine is a service that is invoked from many places in the Data Access System where other File Access Processor components are invoked. o The Work Routine manages routing of control at the successful (commit) or unsuccessful (rollback) conclusion of a work unit (logical grouping of requests into atomic units). It is also invoked from several places in the Data Access System as a service for concluding the work unit processing. o The Pool Routine is a general Data Access System service for allocating and releasing control structures from large blocks of working storage. The routine supports allocating or releasing single or multiple control structures of the same type (chained) with a single invocation. o The Work Request Block Condense Routine supports reduction of multiple changes to the same catalog entry into a single change. The Data Access System utilizes several catalogs for managing file and directory information. Each entry in the Object Catalog, for example, contains descriptive and control information about a particular file. Work Request Blocks (WRBs) are used to save catalog change information from the time of file request processing until the time that the Work Unit is committed. Wh...