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Recovery of Data Base

IP.com Disclosure Number: IPCOM000087807D
Original Publication Date: 1977-Mar-01
Included in the Prior Art Database: 2005-Mar-03
Document File: 2 page(s) / 32K

Publishing Venue

IBM

Related People

Joyce, LA: AUTHOR

Abstract

A typical application of the IBM 3790 communication system is to allow remote locations access to a data base. For example, in a social security application, a complete national data base may be held at a central host computer and regional or local data bases constituting a part of the total data base may be held in a local IBM 3791 Controller. The normal ways of loading a data base into the disk file of a 3791 Controller are either to use the magnetic diskettes locally or to use a teleprocessing link between the host and the controller.

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Recovery of Data Base

A typical application of the IBM 3790 communication system is to allow remote locations access to a data base. For example, in a social security application, a complete national data base may be held at a central host computer and regional or local data bases constituting a part of the total data base may be held in a local IBM 3791 Controller. The normal ways of loading a data base into the disk file of a 3791 Controller are either to use the magnetic diskettes locally or to use a teleprocessing link between the host and the controller.

Where the regional or local data base is large, these two methods can give rise to large downtimes in the event of a data base failure since the local controller cannot be used for normal business transactions while the data base is being restored. However, by using a "soft recovery" technique, normal transactions can be allowed during most of the data base recovery time. The chart shows the sequence of events during data base recovery.

If the data base at the controller fails, the disc files are reformatted. The controller is initialized using the diskettes and the appropriate applications program is loaded from the host system. The host data base is updated with the transactions that have occurred since its last update. The host data base is then copied in the host and a copy is sent to the controller.

During the period that the data base at the controller is incomplete, the operators will interact with th...