Disk array system, controller, and method for verifying command data written to disk drives

• US 6,496,900 B1
• Filed: 09/12/2000
• Issued: 12/17/2002
• Est. Priority Date: 09/12/2000
• Status: Expired due to Fees

• Current Assignee: Summit Data Systems LLC (Acacia Research Corporation)
• Original Assignee: 3Ware Inc. (MACOM Technology Solutions Holdings, Inc.)
• Inventors: McDonald, James A., Biskup, Richard J.
• Primary Examiner(s): Gossage, Glenn
• Application Number:
  US09/659,974
• Time in Patent Office: 826 Days
• Field of Search: 711/112, 711/154, 711/155, 710/19, 710/52, 710/55, 714/42, 714/49, 714/718, 714/805
• US Class Current: 711/112
• CPC Class Codes: G06F 11/1435 using file system or storage system metadata
• CPC Class Codes: G06F 3/0619 in relation to data integrity, e.g. data losses, bit errors
• CPC Class Codes: G06F 3/0659 Command handling arrangements, e.g. command buffers, queues, command scheduling
• CPC Class Codes: G06F 3/0674 Disk device

Abstract

A controller and an associated method, which may be embodied within a disk array system, are disclosed for verifying, the integrity of command data written to a disk drive (preferably an Advanced Technology Attachment or ATA drive) before such command data is used to execute a command. The controller, which may be implemented in automated hardware or firmware residing external to the disk drive, initially writes the command data to the disk drive, and then reads back and verifies this data prior to initiating execution of the command. If the written-out and read-back command data are consistent, the controller initiates execution of the command; otherwise, the controller enters into an error state that prevents the potentially corrupt command data from being used by the disk drive. The controller may also read a status code from the disk drive more than once to reduce the likelihood of misread status information.

Claims

1. A method for verifying the integrity of command data passed to an Advanced Technology Attachment (ATA) disk drive, the method comprising:

writing the command data to a command register block of the ATA disk drive, wherein the command data includes at least one parameter for executing a disk drive command;

prior to initiating execution of the disk drive command by the ATA disk drive, reading the command data back from the command register block and comparing at least a portion of the read-back command data with corresponding command data written to the command register block; and

initiating execution of the disk drive command only if the read-back command data is consistent with the command data written to the command register block.

2. The method of claim 1, wherein the command data includes at least a logical block address (LBA) of the disk drive command.

3. The method of claim 1, further comprising performing at least two reads of status bits of the command register block following completion of the disk drive command by the ATA disk drive, and entering into an error state if an error condition is detected during any of the at least two reads.

4. The method of claim 1, wherein the method is performed by an automated controller device which implements a host side of an ATA interface within automated circuitry.

5. The method of claim 1, wherein the method is embodied within firmware executed by a processor.

6. The method of claim 1, wherein the portion of the read back command data compared with corresponding command data written to the command register block comprises data read from registers 2, 3, 4, and 5 and a portion of register 6.

7. A disk array system, comprising:

a plurality of Advanced Technology Attachment (ATA) disk drives;

a plurality of automated controllers, each automated controller including automated circuitry for communicating with a respective ATA disk drive of the plurality of ATA disk drives over a respective connector; and

a processor which dispatches ATA command blocks to the automated controllers according to a disk array configuration to initiate transfers of input/output data between the ATA disk drives and a host computer;

wherein each automated controller verifies the integrity of ATA command block data written to a respective ATA disk drive by reading back command block data from the respective ATA disk drive and checking the command block data prior to initiating execution of a corresponding disk drive command by the respective ATA disk drive.

8. The disk array system as in claim 7, wherein each automated controller reads back and checks at least a logical block address (LBA) portion of an ATA command block prior to initiating execution of the corresponding disk drive command.

9. The disk array system as in claim 7, wherein each automated controller reads back and checks registers 2, 3, 4, and 5, and a portion of register 6, of an ATA command block.

10. The disk array system as in claim 7, wherein each automated controller writes a command code to a command register of a respective ATA disk drive to initiate command execution upon verifying that the read-back command block data is consistent with the command block data written to the respective ATA disk drive.

11. The disk array system as in claim 7, wherein each automated controller is configured to notify the processor upon detecting that command block data read back from a respective ATA disk drive is inconsistent with the command block data written to the respective ATA disk drive.

12. The disk array system as in claim 7, wherein each automated controller includes a command buffer for receiving a new ATA command block from the processor while a current ATA command block is being processed.

13. The disk array system as in claim 7, wherein each automated controller verifies integrity of status information read from a respective ATA disk drive by reading the status information from the respective ATA disk drive at least twice following completion of a disk drive operation.

14. The disk array system as in claim 7, further comprising an automated array coprocessor coupled to the plurality of automated controllers by a packet-switched bus to transfer input/output data between the ATA disk drives and the host computer.

15. A controller which is adapted to control an Advanced Technology Attachment (ATA) drive over a connector, the controller comprising:

a buffer for transferring input/output (I/O) data between the ATA drive and a bus; and

an automated command/transfer engine which implements a host side of an ATA interface within automated circuitry to control the ATA drive;

wherein the automated command/transfer engine verifies the integrity of command block data written to the ATA drive by reading back and checking the command block data prior to initiating execution of a corresponding disk drive command by the ATA drive.

16. The controller as in claim 15, wherein the automated command/transfer engine verifies integrity of status information read from the ATA drive by reading the same status information at least twice.

17. The controller as in claim 15, wherein the automated command/transfer engine comprises a command buffer which stores multiple ATA command blocks so that a new command block can be dispatched to the ATA drive upon completion by the ATA drive of a current command block.

18. A method for verifying the integrity of command data passed to a disk drive over a connector, the method comprising:

writing the command data to the disk drive over the connector, wherein the command data includes at least one parameter for executing a disk drive command; and

prior to initiating execution of the disk drive command by the disk drive, reading the command data back from the disk drive over the connector, and comparing the read-back command data with the command data written to the disk drive to verify that the command data was successfully written to the disk drive.

19. The method of claim 18, wherein the command data includes at least a logical block address (LBA) of the disk drive command.

20. The method of claim 18, further comprising performing at least two reads over the connector of disk drive status bits following completion of the disk drive command and entering into an error state if an error condition is detected during any of the at least two reads.

21. The method of claim 18, wherein the disk drive is an Advanced Technology Attachment (ATA) disk drive, and the method is performed by an automated controller device which implements a host side of an ATA interface within automated circuitry.

22. The method of claim 18, wherein the method is embodied within firmware executed by a processor.