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DFDSS Dump VSAM Indexed Data Set for Recovery

IP.com Disclosure Number: IPCOM000111447D
Original Publication Date: 1994-Feb-01
Included in the Prior Art Database: 2005-Mar-26
Document File: 2 page(s) / 71K

Publishing Venue

IBM

Related People

Miller, DL: AUTHOR [+2]

Abstract

This new technique is initiated when the user requests a dump (backup) of a VSAM indexed data set. The data is accessed in sequence, validated, reformatted, and written to a dump output data set which can be used as input to data set restore. Various errors that are detected are corrected, allowing the dump to continue. Errors that are detected that can't be corrected result in immediate termination. This technique insures the success of restore if the data set was successfully dumped.

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DFDSS Dump VSAM Indexed Data Set for Recovery

      This new technique is initiated when the user requests a dump
(backup) of a VSAM indexed data set.  The data is accessed in
sequence, validated, reformatted, and written to a dump output data
set which can be used as input to data set restore.  Various errors
that are detected are corrected, allowing the dump to continue.
Errors that are detected that can't be corrected result in immediate
termination.  This technique insures the success of restore if the
data set was successfully dumped.

      This method uses the VSAM index to locate the VSAM data, the
data is written sequentially to an output data set.  The index is not
dumped.  Empty control intervals are not dumped.  Any unrecoverable
errors will be detected at DUMP time and will cause the DUMP to fail.
Therefore, the output data set will not contain any errors that will
prevent the data set from being restored.  Since the data is written
in sequence during the dump process, the restore will execute in the
minimum time.

      The objective is to dump the contents of an indexed VSAM data
set and restore it to any DASD device.  If there are any errors in
the original data set, they must not show up in the restored copy.
If an error cannot be corrected, the DUMP will fail.

      The VSAM indexed data set is dumped by reading the track
containing the first sequence set index record.  The index record is
used to read the tracks that contain the entire data control area.
The index record is used to sequentially locate the data control
intervals.  As each control interval is located, it is moved into an
output...