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Online Data Base Level Control

IP.com Disclosure Number: IPCOM000084897D
Original Publication Date: 1976-Jan-01
Included in the Prior Art Database: 2005-Mar-02
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Benson, PH: AUTHOR [+3]

Abstract

A conventional data base system consists of a host computer having the data base stored therein and a number of remote subsystems or terminals to allow accessing of the data base. In an attempt to decrease the system response time and/or communication costs, it has been suggested that copies of portions of the data base should be stored at the remote subsystems as well as at the host.

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Online Data Base Level Control

A conventional data base system consists of a host computer having the data base stored therein and a number of remote subsystems or terminals to allow accessing of the data base. In an attempt to decrease the system response time and/or communication costs, it has been suggested that copies of portions of the data base should be stored at the remote subsystems as well as at the host.

Most data bases need to be updated periodically. After any change to a distributed data base system such as that described above, there is a need to ensure that each remote subsystem accesses the latest version of the data base. This need does not arise with a nondistributed data base, since in this case any changes need only be made at the host.

This solution to the problem of updating a distributed data base system is to employ two procedures. In the normal update procedure, all subsystems would need to be "logged off", for example, during the middle of the night or another low use period. On restart, each subsystem would receive delete instructions and would be required to rebuild its local data base to the new level, before any transactions could be started at that subsystem. The second procedure is designed to allow emergency updating of the local data base between normal update procedures. In theory, it could be arranged for the host to keep a record of the data base stored at each remote system, and for the host to signal those subsystems which...