FILE SYSTEM FOR STORAGE DEVICE WHICH USES DIFFERENT CLUSTER SIZES

• US 20100082537A1
• Filed: 09/29/2009
• Published: 04/01/2010
• Est. Priority Date: 09/29/2008
• Status: Abandoned Application

• Current Assignee: SanDisk IL Ltd. (Western Digital Corporation)
• Original Assignee: SanDisk IL Ltd. (Western Digital Corporation)
• Inventors: Lasser, Menahem
• Application Number:
  US12/568,962
• Publication Number:
  US 20100082537A1
• Time in Patent Office: Days
• US Class Current: 707/610
• CPC Class Codes: G06F 16/13 File access structures, e.g. distributed indices arrangements of input from, or output to, record carriers G06F3/06
• CPC Class Codes: G06F 3/0608 Saving storage space on storage systems
• CPC Class Codes: G06F 3/0643 Management of files
• CPC Class Codes: G06F 3/0671 In-line storage system

Abstract

A file system for managing files in a storage device in a more optimal way by providing allocation units or clusters with non-uniform sizes. Clusters of at least two different sizes are allocated in a common partition of a storage device, such as a hard disk drive, other magnetic media, optical media and semiconductor storage such as flash memory and other non-volatile memory. At least two clusters are allocated in the storage device for storing the files. First and second allocated clusters are allocated to first and second portions of the storage device, respectively, and contain different numbers of sectors. One or more optimum cluster sizes can be selected for storing the files without knowing the size of the files in advance, based on factors such as whether compression is to be performed, file type, access patterns of a calling application, and an identification of the calling application.

Claims

1. A storage system, comprising:

a storage device; and

one or more processors executing code to manage the storage device, the one or more processors;

a. provides data to be stored in one or more files in the storage device, each file comprising a plurality of sectors of data;

b. without knowing a size of the one or more files, allocates at least two clusters in the storage device for storing the one or more files, wherein the at least two clusters are in a common partition of the storage device, and wherein a first one of the allocated clusters is allocated to a first portion of the storage device and contains a first number of sectors, a second one of the allocated clusters is allocated to a different, second portion of the storage device and contains a second number of sectors, and the first and second numbers of sectors are different from each other; and

c. stores the one or more files in the allocated clusters.

2. The storage system of claim 1, wherein:

the one or more processors maintain a file directory which identifies at least one file and a corresponding starting cluster which is allocated to the at least one file.

3. The storage system of claim 1, wherein:

the one or more processors maintain a file allocation table which links the clusters of at least one file.

4. The storage system of claim 1, wherein:

the one or more processors choose a suitable cluster size for writing at least one file based on whether the at least one file is to undergo compression before being stored on the storage device.

5. The storage system of claim 4, wherein:

the one or more processors allocate a smaller cluster size to the at least one file if it is to undergo compression before being stored on the storage device, and allocate a larger cluster size to the at least one file if it is not to undergo compression before being stored on the storage device.

6. The storage system of claim 1, wherein:

the one or more processors choose a suitable cluster size for writing at least one file based on an access pattern of a calling application which creates the at least one file.

7. The storage system of claim 1, wherein:

the one or more processors choose a suitable cluster size for writing at least one file based on a file type of the at least one file.

8. The storage system of claim 1, wherein:

the one or more processors choose a suitable cluster size for writing at least one file based on a file name extension of the at least one file.

9. The storage system of claim 1, wherein:

the one or more processors choose a suitable cluster size for writing at least one file based on an identity of a calling application which creates the at least one file.

10. The storage system of claim 1, wherein:

the storage device comprises flash memory.

11. A computer-implemented method for writing data to a storage device, comprising:

a. providing data to be stored in one or more files in the storage device, each file comprising a plurality of sectors of data;

b. without knowing a size of the one or more files, allocating at least two clusters in the storage device for storing the one or more files, wherein the at least two clusters are in a common partition of the storage device, and wherein a first one of the allocated clusters is allocated to a first portion of the storage device and contains a first number of sectors, a second one of the allocated clusters is allocated to a different, second portion of the storage device and contains a second number of sectors, and the first and second numbers of sectors are different from each other; and

c. storing the one or more files in the allocated clusters.

12. The computer-implemented method of claim 11, further comprising:

providing a file directory which identifies at least one file and a corresponding starting cluster which is allocated to the at least one file.

13. The computer-implemented method of claim 11, further comprising:

providing a file allocation table which links the clusters of at least one file.

14. The computer-implemented method of claim 11, further comprising:

choosing a suitable cluster size for at least one file based on whether the at least one file is to undergo compression before being stored on the storage device.

15. The computer-implemented method of claim 14, further comprising:

allocating a smaller cluster size to the at least one file if it is to undergo compression before being stored on the storage device, and allocating a larger cluster size to the at least one file if it is not to undergo compression before being stored on the storage device.

16. The computer-implemented method of claim 11, further comprising:

choosing a suitable cluster size for at least one file based on an access pattern of a calling application which creates the at least one file.

17. The computer-implemented method of claim 11, further comprising:

choosing a suitable cluster size for at least one file based on a file type of the at least one file.

18. The computer-implemented method of claim 11, further comprising:

choosing a suitable cluster size for at least one file based on an identity of a calling application which calls the file system to create the at least one file.

19. The computer-implemented method of claim 11, wherein:

the storage device comprises flash memory in a flash memory device, and the storing is responsive to a request which is received from a host device which is external to the flash memory device.