Browse Prior Art Database

Method for corrupt directory recovery

IP.com Disclosure Number: IPCOM000021608D
Original Publication Date: 2004-Jan-27
Included in the Prior Art Database: 2004-Jan-27
Document File: 1 page(s) / 46K

Publishing Venue

IBM

Abstract

Following a crash or other unforeseen circumstances, it is sometimes necessary for an operating system to rebuild a corrupt directory/library. Described is a method for quick recovery.

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This is the abbreviated version, containing approximately 52% of the total text.

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Method for corrupt directory recovery

Disclosed is a method for fast recovery of a corrupt library or directory in an operating system.

     The problem solved by this invention is the recovery of libraries on a machine where it is necessary. For example, this might be needed if the machine crashes, and information within the libraries becomes corrupt. The only known solution to this problem is to look at all of the objects on a system and determine what library the object belongs in order to rebuild the corrupt library. The drawback to this solution is that it requires page faulting of every object on the system. The amount of time required for this has a lot of dependencies (size of system, number of objects on the system, etc) and can vary widely, from minutes, to several hours, to days.

     This invention uses an alternate method for library recovery. Instead of rebuilding a corrupt library by page faulting every single object on a machine to identify its owning library, make a list of all the known objects in the uncorrupted libraries. Then the only objects that need to be page faulted are ones that are not accounted for in the list. This greatly reduces the number of page faults needed to perform library recovery, and in turn, reduces the time required to perform this task. This is because for the objects in uncorrupted libraries, the only thing that needs to be page faulted is the list of objects in that library, as opposed to each object itself. For example, if an uncorrupted library contains 10,000 objects, the current method would require 10,000 page fault...