Method and system for improving the contiguity of sectors of a file

United States Patent m

Letwin

[54] METHOD AND SYSTEM FOR IMPROVING THE CONTIGUITY OF SECTORS OF A FILE

[75] Inventor: James G. Letwin, Kirkland, Wash.

[73] Assignee: Microsoft Corporation, Redmond, Wash.

[21] Appl. No.: 299,542
[22] Filed: Sep. 1,1994

Related U.S. Application Data

[62] Division of Ser. No. 400,533, Aug. 29, 1989, Pat. No. 5,371,885.

[51] Int. CI.6 G06F 17/30; G06F 12/00

[52] U.S. CI 395/621; 364/DIG. 1;

364/DIG. 2; 395/412; 395/181

[58] Field of Search 395/425, 444,

395/427, 412, 497.01, 497.04, 181, 182.01, 600; 364/DIG. 1, DIG. 2

[56] References Cited

U.S. PATENT DOCUMENTS

4,435,752 3/1984 Winkelman 364/200

4,468,728 8/1984 Wang 364/200

4,825,354 4/1989 Agrawal et al 364/200

4,945,475 7/1990 Bruffeyetal 364/200

4,953,080 8/1990 Dysart et al 364/200

5,008,820 4/1991 Christopher, Jr. 364/200

5,034,914 7/1991 Osterlund 364/900

5,047,918 9/1991 Schwartz et al 364/200

5,068,842 11/1991 Naito 369/32

5,398,142

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US005608901A [ii] Patent Number: 5,608,901 [45] Date of Patent: Mar. 4, 1997

OTHER PUBLICATIONS

Maurice, J. Bach, "The Design of the UNIX Operating System", Prentice-Hall, London, 1986, pp. 22-24; 62; 68-81.

Matt Koehler, "GFS Revisited or How I Lived With Four Different Local File Systmes", Proceedings of the Summer 1987 Usenix Conference, Jun. 8, 1987, Phoenix, Arizona, pp. 291-305.

New York, "Directory for Disk With Write-Once Storage Medium", IBM Technical Disclosure Bulletin, vol. 30, No. 6, Nov. 1987, New York, pp. 137-138.

Primary Examiner—Tod R. Swann
Assistant Examiner—Tuan V. Thai
Attorney, Agent, or Firm—Seed and Berry LLP

[57] ABSTRACT

A method and system for storing file system state information within sectors of the file system. File system information includes pointers to top-level file system structures, such as free space bitmaps, a bad block list, a directory block band, and a root directory. The file system state information is classified into two groups: frequently-updated information and infrequently-updated information. The two groups are stored on separate sectors in order to minimize write operations performed on the infrequently-updated information and thereby reduce the risk of the infrequently-updated information being corrupted.

3 Claims, 17 Drawing Sheets

Microfiche Appendix Included

3/1995 Davy 360/48

(.lio Microncne, 4 JPages)