Method and apparatus for use of a host address to validate accessed data

• US 6,098,190 A
• Filed: 08/04/1998
• Issued: 08/01/2000
• Est. Priority Date: 08/04/1998
• Status: Expired due to Fees

• Current Assignee: Hewlett-Packard Company (HP Inc.)
• Original Assignee: Hewlett-Packard Company (HP Inc.)
• Inventors: Jacobson, Michael B., Rust, Robert A., Grund, Christine
• Primary Examiner(s): Moise, Emmanuel L.
• Application Number:
  US09/129,031
• Time in Patent Office: 728 Days
• Field of Search: 714/763, 714/6, 714/7, 714/48, 714/52, 714/53, 714/702, 714/718, 714/719, 714/766, 714/805, 714/819, 714/4, 714/114
• US Class Current: 714/763
• CPC Class Codes: G06F 11/1076 Parity data used in redundant arrays of independent storages, e.g. in RAID systems

Abstract

A memory system constructed in accordance with the invention receives data blocks and associated host LBAs from a host processor. The memory subsystem initially associates a check value with each received data block, each check value dependent upon a host LBA that is associated with the respectively received data block. The memory subsystem stores each received data block and associated check value as an "extended" data block. Thereafter, the memory subsystem, in response to a host processor request to access data corresponding to the associated host LBA, recovers the stored extended data block and determines from the check value stored therewith, if the address of the corresponding data and that provided by the host processor correspond. If the addresses correspond, the data block is transmitted to the host processor. If not, an error message is generated.

Claims

1. A memory subsystem for receiving a stream of data from the host processor, said stream including associated host logical block addresses (LBAs), said memory subsystem comprising:

first means for associating a check value with each received block of data, each said check value dependent upon a host LBA that is associated with a respectively received block of data;

second means for storing as extended blocks, at least each said received block of data and an associated check value; and

third means responsive to a read request from said host processor, accompanied by a host LBA, for retrieving from said second means, an extended block, and for determining a correspondence or lack of correspondence of retrieved data in said extended block to data designated by said host LBA, through use of said check value retrieved as part of said extended data block.

2. The memory subsystem as recited in claim 1, wherein said third means causes transmission of said block of data to said host processor only if said check value retrieved from said extended block indicates that data in said extended block correspond to data in a data block denoted by said host LBA.

3. The memory subsystem as recited in claim 1, wherein said second means stores in each extended data block both a check value and said host LBA.

4. The memory subsystem as recited in claim 3, wherein said third means employs said host LBA received from said host processor to calculate a check value and compares said check value with said check value recovered from an extended block to determine said correspondence.

5. The memory subsystem as recited in claim 1, wherein each said received block of data is received in a first block size format, said second means stores each said received block of data and associated check value as extended blocks in a second block size format, and said third means accesses stored extended blocks based upon said second block size format.

6. The memory subsystem as recited in claim 1, wherein said first means calculates a check value for a received block of data based upon use of a host LBA as a seed value.

7. The memory subsystem as recited in claim 6, wherein said third means calculates from said check value, a host LBA value and determines if said host LBA value that is calculated is coincident with a host LBA received from said host processor.

8. A method for controlling a memory subsystem that receives a stream of data from a host processor, said stream including associated host logical block addresses (LBAs), said method comprising the steps of:

a) associating a check value with each received block of data, each said check value dependent upon a host LBA that is associated with a respectively received block of data;

b) storing as extended blocks, at least each said received block of data and an associated check value; and

c) responding to a read request from said host processor, accompanied by a host LBA, by retrieving an extended block, and determining a correspondence or lack of correspondence of a block of retrieved data in said extended block, to data designated by said host LBA, through use of said check value retrieved as part of said extended data block.

9. The method as recited in claim 8, wherein step c) transmits said block of retrieved data to said host processor only if said check value retrieved from said extended block indicates that said block of retrieved data correspond to data in a data block denoted by said host LBA.

10. The method as recited in claim 8, wherein said step b) stores in each extended data block, both a check value and said host LBA.

11. The method as recited in claim 8, wherein step c) employs said host LBA received from said host processor to calculate a check value and compares said check value with said check value recovered from an extended block to determine said correspondence.

12. The method as recited in claim 8, wherein each said received block of data is received in a first block size format, said step b) stores each said received block of data and associated check value as extended blocks in a second block size format, and step c) accesses stored extended blocks based upon said second block size format.

13. The method as recited in claim 8, wherein step a) calculates a check value for a received block of data based upon use of a host LBA as a seed value.

14. The method as recited in claim 13, wherein step c) calculates from said check value, a host LBA value and determines if said host LBA value that is calculated is coincident with a host LBA received from said host processor.