Browse Prior Art Database

Method for Detecting VALID Gaps in Logical Sector Numbers

IP.com Disclosure Number: IPCOM000063277D
Original Publication Date: 1985-Mar-01
Included in the Prior Art Database: 2005-Feb-18

Publishing Venue

IBM

Related People

Authors:
Fichtner, LG McKelley, CR Pierschalla, BR [+details]

Abstract

A method is described for determining if a gap that exists in logical sector numbers on a diskette or disk for a text processing system is a valid gap caused by the operating system's deallocation of defective sectors. When an operating system's dataset recovery utility unchains groups of logical sectors from a file, self-identifying logical sectors are used to detect that these logical sectors are unchained. However, a logical sector may become unchained through an error in the machine or by a program failure. It is important to distinguish between these two types of gaps to avoid data integrity problems. Recovery of all or part of the data depends upon valid sector numbering so the following method is used to determine if the gaps are valid. A two-pass recovery technique is used.