Browse Prior Art Database

Enhanced Database Recovery From Abnormal System Termination

IP.com Disclosure Number: IPCOM000101992D
Original Publication Date: 1990-Oct-01
Included in the Prior Art Database: 2005-Mar-17
Document File: 2 page(s) / 76K

Publishing Venue

IBM

Related People

Vriezen, JJ: AUTHOR

Abstract

A method is described which allows for a less severe abnormal termination for many types of software and hardware failures, thereby minimizing recovery time for the subsequent restart of the system.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 52% of the total text.

Enhanced Database Recovery From Abnormal System Termination

       A method is described which allows for a less severe
abnormal termination for many types of software and hardware
failures, thereby minimizing recovery time for the subsequent restart
of the system.

      When an unrecoverable condition occurs in a computer system,
the system will typically have code to shut itself down in as
graceful a manner as possible.  The level of "gracefulness" is
dependent on what level of hardware or software the error occurs
and/or is detected. For instance, if utility electrical power fails,
and their is no Uninterruptable Power Supply, all activity is stopped
immediately and no graceful shutdown is possible.

      If, on the other hand, the error occurs at a very high level in
the system software, a lot of graceful shutdown processing can occur
including closing all open files and forcing all outstanding main
storage changes to DASD.

      A particular class of failure on a computer system is where
main storage changes have been preserved and reflected to DASD.  This
can happen when all main storage pages are written to their
respective disk locations by storage management prior to final
termination, or when a main storage dump is taken and the dump is
used on the subsequent IPL to update all the appropriate DASD
locations.  The latter case occurs when a "non-dataloss" DASD failure
occurs, a very common case.  The operation of writing all changed
pages to DASD before terminating the machine is called "shutdown."

      When an operation which alters an object begins, a bit within
the obje...