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A Method and System for Rebuilding a Data Set Control Block Residing in a Volume Table of Contents

IP.com Disclosure Number: IPCOM000240756D
Publication Date: 2015-Feb-26
Document File: 1 page(s) / 39K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method and system for rebuilding a Data Set Control Block (DSCB) residing in a Volume Table of Contents (VTOC).

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A Method and System for Rebuilding a Data Set Control Block Residing in a Volume Table of Contents

Generally, Direct Access Storage Devices (DASD) includes a volume map, which can be used by an operating system to

manage user data and free space on a device. The conventional operating systems which may include, but need not be limited to, a z/OS and the like having the volume map is known as a Volume Table of Contents (VTOC). User data on a volume is stored in the form of data sets and pointers to the data sets are stored in a Data Set Control Block (DSCB) record included in the VTOC. The VTOC is composed of a set of directory blocks. When a data set is created, one or more available directory blocks is used to record meta data about this data set. This directory block remains associated

with the data set until the data set is deleted. At that time, the directory block(s) can be recycled.

Thus, when a data set is deleted the actual data may remain same; however, the pointer in the DSCB corresponding to the actual data is deleted. If a user determines that the data set deleted is an error. The user cannot immediately recover the data. In order to recover the data, the user has to perform a backup by utilizing any other media which may include, but need not be limited to, DASD volume, tape and the like prior of deleting the data set. However, many writes could have occurred between the backup time and the deleted time which cannot be recovered. Therefore, the meth...