Browse Prior Art Database

Fault Tolerant Format

IP.com Disclosure Number: IPCOM000020613D
Original Publication Date: 2003-Dec-03
Included in the Prior Art Database: 2003-Dec-03
Document File: 2 page(s) / 9K

Publishing Venue

IBM

Abstract

Disclosed is a software format that offers the fault tolerance and redundancy of RAID 5 on a single media. The format allows the user to recover data from media with faults, defects, or other damage.

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Fault Tolerant Format

Disclosed is a software format that offers the fault tolerance and redundancy of RAID 5 on a single media. The format allows the user to recover data from media with faults, defects, or other damage.

Redundant Array of Inexpensive Disks (RAID) is a feature commonly found in servers or workstations where it is critical to recover from media faults. Examples of media include hard drives, CDROM, CDRs, CDRWs, DVDs, compact flash, and similar memory devices. The RAID logic is usually stored in software or firmware on an I/O controller dedicated to RAID functionality. There are many levels or versions of RAID that were designed for specific user I/O needs. RAID 5 is a level used to spread data or parity across three of more media. If one media were to fail, it could be rebuilt, or the data could be reconstructed, on another good media from the data or parity on the other two media.

The disclosed software format offers RAID 5 fault tolerance and redundancy on a single media. For example, if a user scratches an area a CDROM, without this software format, the data located in the scratched area would be permanently lost. Because the software format requires only one media, it introduces a much lower price point to users who require media fault tolerance and redundancy.

Media can be physically broken down into units. These units are sometimes referred to as blocks, tracks, or sectors depending on the media type. In the disclosed software format, these units can become "virtual separate media". With three "virtual separate media", RAID 5 can be implemented.

Unlike today's RAID implementations, the disclosed software format:
a) Determines available media size. For example, it determines how many megabytes are free on a harddrive.
b) Determines media type for access method. For example, harddisks and CDROMs access data or units differently. The disclosed format determines the best unit layout for a given media for optimal access performance.
c) Using information deter...