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Backup and Recovery for a Large Data Base

IP.com Disclosure Number: IPCOM000039298D
Original Publication Date: 1987-May-01
Included in the Prior Art Database: 2005-Feb-01
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Tiller, JR: AUTHOR

Abstract

In some computer systems, where a SAVE LIBRARY command is used to save a library containing a limited number of objects, e.g., 4000 objects, for a data base containing a greater number of objects, the following procedure is used. First, a library descriptor is saved on tape so that the library can be rebuilt later. Then, a list of all of the library files to be saved is saved on the tape so that the restoration process will recognize the order of the files. Next, the data base files are saved in groups. For instance, the master physical and logical files of items are saved together using a SAVE OBJECT command. The item relationship files are then saved as a group. After all of the data base files are saved, each of the multi-member source (text) files is saved individually.

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Backup and Recovery for a Large Data Base

In some computer systems, where a SAVE LIBRARY command is used to save a library containing a limited number of objects, e.g., 4000 objects, for a data base containing a greater number of objects, the following procedure is used. First, a library descriptor is saved on tape so that the library can be rebuilt later. Then, a list of all of the library files to be saved is saved on the tape so that the restoration process will recognize the order of the files. Next, the data base files are saved in groups. For instance, the master physical and logical files of items are saved together using a SAVE OBJECT command. The item relationship files are then saved as a group. After all of the data base files are saved, each of the multi-member source (text) files is saved individually. The multi-member source files are created with a maximum member limit of 4000 members so as not to exceed the limit during the SAVE OBJECT command. During the RESTORE procedure, the library descriptor is restored to a temporary library and read so that an exact replica of the old library can be constructed. Next, the list of files is restored to the temporary library so that the files can be restored in the same order in which they were saved. This is necessary because the SAVE takes place on the tape and the order of the objects is important. Finally each multi- member source (text) file is restored in the correct sequence.

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