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A method of storing data with redundancy check code to 512-Byte sector hard disk drive

IP.com Disclosure Number: IPCOM000011898D
Original Publication Date: 2003-Mar-25
Included in the Prior Art Database: 2003-Mar-25
Document File: 3 page(s) / 23K

Publishing Venue

IBM

Abstract

This article describes a method to read/write data that has non 512-byte sector format from/to a disk drive which has 512-byte sector format.

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  A method of storing data with redundancy check code to 512-Byte sector hard disk drive

   Disclosed is a system for a storage enclosure with a disk drive which has 512-byte sector format to be used for the high reliability system.

This method provides the function to write and read non 512-byte data on the storage system to and from 512-byte sector block on the disk drive.

Generally the system which has high reliability adds redundancy information less than 16 bytes to 512-byte user data to store into the disk drive. The redundancy information includes a longitudinal redundancy check code (LRC) and others which is provided for data integrity. The high performance disk drive which has SCSI and Fibre channel interface supports non 512-byte sector size, however a standard ATA disk drive does not support non 512-byte sector format and is not able to read and write data with redundancy information for a high reliability storage system.

Figure. 1 illustrates the system overview to store data which has non 512-byte sector format to the disk drive which has 512-byte sector format. The storage system usually uses SCSI protocol on fibre channel or SCSI physical connection. Therefore the protocol conversion is also required for storing data if the disk drive which has 512-byte sector format is the standard ATA disk drive or the serial ATA disk drive.

Storage Enclosure

Non 512-byte 512-byte sector sector format

Protocol Converter

format

Sector size converter

Disk Drives

Host System

FC-AL or SCSI

Figure. 1 System overview

The protocol convertor has a host interface and a disk drive interface, and realign incoming data from a host interface for converting sector format and forward it to a disk drive interface to transmit to a disk drive. A block diagram of the protocol convertor is shown in Figure. 2..

System Bus

Memory

Controller

Memory Controller

- Instruction - Sector data buffer

DMA

DMA

Host System Non 512-byte sector format

Host I/F Protocol Engine (SCSI or Fibre Channel

ATA Controller + Disk Drive I/F

ATA Disk Drive (512-byte Block)

Figure. 2 Block Diagram of the protocol convertor

The data format on the host system is as follow:

1

Page 2 of 3

Block 0 Block 1 Block n

512 Bytes Data

1-16 Bytes LRC+

512 Bytes Data

1-16 Bytes LRC+

...

512 Bytes Data

1-16 Bytes LRC+

528 Bytes / Block

Figure. 3 Data format on the host system

The sector size conversion is provided by realigning data format as follow:

Block 0 Block 1 Block 31 LRC+

1 Page (16.5 Kbytes)

Figure. 4 Data format on a disk drive

The host interface controller of a sector size convertor receives the command frame from the host system and decodes commands. When the write command is received, host interface controller forwards the payload data to the sector data buffer memory. The payload data and the redundancy information is stored into...