Maintaining cache integrity by recording write addresses in a log

• US 7,299,379 B2
• Filed: 06/27/2003
• Issued: 11/20/2007
• Est. Priority Date: 06/27/2003
• Status: Active Grant

• Current Assignee: SK Hynix NAND Product Solutions Corporation (SK Hynix Inc.)
• Original Assignee: Intel Corporation
• Inventors: Royer, Robert J. Jr., Coulson, Richard L.
• Primary Examiner(s): PEIKARI, BEHZAD
• Application Number:
  US10/607,772
• Publication Number:
  US 20040268026A1
• Time in Patent Office: 1,607 Days
• Field of Search: 711/141
• US Class Current: 714/20
• CPC Class Codes: G06F 11/1417 Boot up procedures
• CPC Class Codes: G06F 11/1471 involving logging of persistent data for recovery
• CPC Class Codes: G06F 12/0802 Addressing of a memory level in which the access to the desired data or data block requires associative addressing means, e.g. caches
• CPC Class Codes: G06F 12/0804 with main memory updating G06F12/0806 takes precedence

Abstract

An apparatus, as well as systems, methods, and articles can operate to record the address of write operations to a memory cached by a non-volatile cache prior to executing an operating system cache driver. In an embodiment, a non-volatile cache may be implemented by creating a device option read only memory (ROM), or modifying the associated computer basic input-output system (BIOS) to trap software interrupts associated with disk and other media access requests. Associated addresses, such as logical block addresses, can be stored in a log for data that is modified. The resulting log can be stored in a non-volatile medium, including the cache itself. If the available log space is not large enough to record all write activity prior to loading operating system drivers, a flag may be set to indicate the overrun condition.

Claims

1. A method, comprising:

recording an address of a write operation to a memory having information cached by a non-volatile cache prior to executing an operating system cache driver associated with the non-volatile cache;

recording the address of the write operation in a log;

setting a flag to indicate an overrun of the log; and

invalidating the information if the flag is set.

2. The method of claim 1, wherein the log is stored in a memory comprising at least one of a static random access memory (SRAM), a dynamic random access memory (DRAM), a flash memory, and a polymer ferroelectric RAM (PFRAM).

3. The method of claim 1, further comprising:

detecting the write operation.

4. The method of claim 3, wherein detecting the write operation further comprises:

trapping an interrupt request.

5. The method of claim 1, further comprising:

modifying data corresponding to the address of the write operation.

6. The method of claim 5, wherein modifying the data corresponding to the address of the write operation further comprises:

updating the data corresponding to the address of the write operation.

7. The method of claim 5, wherein modifying the data corresponding to the address of the write operation further comprises:

invalidating the data corresponding to the address of the write operation.

8. An article comprising a machine-accessible medium having associated data, wherein the data, when accessed, results in a machine performing:

recording an address of a write operation to a memory having information cached by a non-volatile cache prior to executing an operating system cache driver associated with the non-volatile cache;

recording the address of the write operation in a log;

setting a flag to indicate an overrun of the log; and

invalidating the information if the flag is set.

9. The article of claim 8, wherein the log is included in a non-volatile memory.

10. An apparatus, comprising:

a non-volatile cache;

a first memory to store an address associated with a write operation to a second memory having information cached by the non-volatile cache prior to executing an operating system cache driver associated with the non-volatile cache;

the first memory to record the address of the write operation in a log; and

a machine to set a flag to indicate an overrun of the log; and

the machine to invalidate the information if the flag is set.

11. The apparatus of claim 10, wherein the address is a logical block address.

12. The apparatus of claim 10, wherein the first memory to store an address comprises a non-volatile memory.

13. The apparatus of claim 10, further comprising:

a module to receive an interrupt request associated with the write operation.

14. The apparatus of claim 13, wherein the interrupt request is a basic input-output system Int13h request.

15. A system, comprising:

a non-volatile cache;

a first memory to store an address associated with a write operation to a second memory having information cached by the non-volatile cache prior to executing an operating system cache driver associated with the non-volatile cache;

a processor coupled to the first memory to store an address;

the first memory to record the address of the write operation in a log;

the processor to set a flag to indicate an overrun of the log;

the processor to invalidate the information if the flag is set; and

a display coupled to the processor.

16. The system of claim 15, further comprising:

a module to receive an interrupt request associated with the write operation.

17. The system of claim 16, wherein the module is included in a device option memory.

18. The system of claim 16, wherein the module is included in a basic input-output system.

19. The system of claim 15, wherein the first memory to store an address comprises a non-volatile memory to store the log including a plurality of memory addresses including the address of the write operation.