Computer system having logically ordered cache management

• US 20070005894A1
• Filed: 06/09/2006
• Published: 01/04/2007
• Est. Priority Date: 07/01/2005
• Status: Active Grant

• Current Assignee: Malikie Innovations Limited (Key Patent Innovations Limited)
• Original Assignee: QNX Software Systems Company (Blackberry Limited)
• Inventors: Dodge, Dan
• Granted Patent: US 7,698,495 B2
• Time in Patent Office: Days
• US Class Current: 711/118
• CPC Class Codes: G06F 12/0866 for peripheral storage systems, e.g. disk cache
• CPC Class Codes: G06F 2212/214 Solid state disk
• CPC Class Codes: G06F 2212/462 Track or segment

Abstract

A computer system is set forth that includes a processor, general memory storage, and cache memory for temporarily storing selected data requested from the general memory storage. The computer system also may include file system software that is executed by the processor. The file system software may be used to manage the file data and the structure of the file system for files stored on the general memory storage. Management of the cache memory is placed under the control of cache management software. The cache management software is executed by the processor to manage the contents of the cache memory pursuant to cache hit and cache miss criterion. Sections of the cache memory are organized by the cache management software based on logical addresses of file data requested from the general memory storage.

Claims

1. A computer system comprising:

a processor;

general memory storage;

cache memory for temporarily storing selected data requested from the general memory storage;

cache management software executable by the processor for managing the contents of the cache memory pursuant to cache hit and cache miss criterion, where the cache management software organizes memory sections of the cache memory based on logical addresses of file data requested from the general memory storage.

2. A computer system as claimed in claim 1, further comprising a write buffer for temporarily storing selected data that is to be written from the cache memory to the general memory storage.

3. A computer system as claimed in claim 2, where the cache management software logically organizes the contents of the write buffer, and where logical organization of the contents of the write buffer occurs prior to the writing of the write buffer contents to the general memory storage.

4. A computer system as claimed in claim 3, further comprising file system software executable by the processor for managing file data and file system structure of files stored on the general memory storage.

5. A computer system as claimed in claim 4, where the file system software allocates a new memory area in the general memory storage based on a total amount of memory space needed to relocate the original data items of a given file and the data items of the write buffer for the given file to the new memory area.

6. A computer system as claimed in claim 5, where the file system software logically organizes the given file in the new memory area.

7. A computer system as claimed in claim 1, where the general memory storage comprises flash-like memory.

8. A computer system as claimed in claim 1, where the general memory storage comprises rotating disk memory.

9. A computer system comprising:

a processor;

general memory storage;

cache memory for temporarily storing selected data requested from the general memory storage;

cache management software executable by the processor for managing the contents of the cache memory pursuant to cache hit and cache miss criterion, where the cache management software allocates a first memory section of the cache memory to logically contiguous items of a first file stored in the general memory storage and a second memory section of the cache memory to logically contiguous items of a second file stored in the general memory storage.

10. A computer system as claimed in claim 9, further comprising a write buffer for temporarily storing selected items of the first and/or second file that are to be written from the cache memory to the general memory storage.

11. A computer system as claimed in claim 10, where the cache management software logically organizes the contents of the write buffer, and where logical organization of the contents of the write buffer occurs prior to the writing of the write buffer contents to the first and/or second files in the general memory storage.

12. A computer system as claimed in claim 11, further comprising file system software executable by the processor for managing file data and file system structure of files stored on the general memory storage.

13. A computer system as claimed in claim 12, where the file system software allocates a new memory area in the general memory storage for the first file based on a total amount of memory space needed to relocate the original items of the first file and the items of the write buffer for the first file to the new memory area in the general memory storage.

14. A computer system as claimed in claim 13, where the file system software further allocates a further new memory area for the second file in the general memory storage based on a total amount of memory space needed to relocate the original items of the second file and the items of the write buffer for the second file to the further new memory area in the general memory storage.

15. A computer system as claimed in claim 13, where the file system software logically organizes the first file in the new memory area.

16. A computer system as claimed in claim 14, where the file system software logically organizes the second file in the further new memory area.

17. A computer system as claimed in claim 9, where the general memory storage comprises flash-like memory.

18. A computer system as claimed in claim 9, where the general memory storage comprises rotating disk memory.

19. A method for operating a computer system having general memory storage and cache memory, the method comprising:

receiving a read request for a data item of a file stored in the general memory storage;

servicing the request for the data item from cache memory if the data item is present in cache memory;

allocating a predetermined, contiguous area of cache memory to the file from which the data item was requested;

copying a plurality of data items of the file stored in the general memory storage to the allocated area of the cache memory so that the plurality of data items of the file are logically ordered in the allocated area of the cache memory.

20. A method as claimed in claim 19, further comprising temporarily storing selected data that is to be written from the cache memory to the general memory storage in a write buffer.

21. A method as claimed in claim 20, further comprising:

logically organizing the contents of the write buffer; and

writing the logically organized contents of the write buffer to the general memory storage.

22. A method as claimed in claim 21, further comprising:

allocating a new memory area in the general memory storage based on a total amount of memory space needed to relocate the original items of the file and the items of the write buffer for the file to the new memory area; and

logically organizing the file in the new memory area.