Method and mechanism for freeing disk space in a file system

Patent 6023744 Issued on February 8, 2000. Estimated Expiration Date:

March 7, 2017. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.

Abstract Claims Description Full Text

Patent References

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Inventors

Assignee

Microsoft Corporation

Application

No. 813621 filed on 03/07/1997

US Classes:

711/4, Dynamic-type storage device (e.g., disk, tape, drum)707/205, File allocation711/111Accessing dynamic storage device

Examiners

Primary: Lane, Jack A.

Attorney, Agent or Firm

Michalik & Wylie, PLLC

International Class

G06F 017/30

Abstract

A method and mechanism for rapidly freeing storage space allocated to any logical portion of a file. An application program provides the file system with information indicating a block of logical data to free. The file system converts the information to the physical allocation units such as the clusters corresponding to the logical block of data, and manipulates the file's meta data to indicate that the physical space is no longer allocated to the file. The file system then adds the space to disk free space. Applications such as merge applications and those managing FIFO queues may use the method and mechanism to shrink a file from the start of the file toward the end thereof without copying the logical data or adjusting internal pointers relative to the logical file data.