Browse Prior Art Database

File Synchronization Integrity

IP.com Disclosure Number: IPCOM000121533D
Original Publication Date: 1991-Sep-01
Included in the Prior Art Database: 2005-Apr-03
Document File: 1 page(s) / 47K

Publishing Venue

IBM

Related People

Kinser, CE: AUTHOR

Abstract

Disclosed is a process which insures the detectability of incomplete operations on a set of interdependent files.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 65% of the total text.

File Synchronization Integrity

      Disclosed is a process which insures the detectability of
incomplete operations on a set of interdependent files.

      A set of interdependent files is any collection of two or more
files which are related in such a way that the integrity of the data
contained in the set is lost if an operation to more than one file
terminates before all affected files have been modified to
completion.  Such an operation is called an "interdependent update".

      Each file contains a synchronization-number field. One of these
files is designated as the Standard file, and also contains the
previous-synchronization-number field and the synchronization-status
field, which has three states: SYNCHRONIZED, meaning the integrity of
the files is reliable ("the files are synchronized"); SYNCHRONIZING,
meaning the process of re-synchronizing the files is in progress;
and, UPDATING, meaning an interdependent update is in progress.

      Before an interdependent update is performed, the
synchronization-status field is set to SYNCHRONIZING. Then the
updates are performed. Afterwards, the files must be re-synchronized.
The synchronization-number field is copied to the
previous-synchronization-number field on the same physical write
operation as setting the synchronization-status field to
SYNCHRONIZING. A new and unique synchronization- number field is
generated and written to all files in the set (the method of
generating a unique number is not d...