Browse Prior Art Database

Method and Apparatus for an Integrated Temporary and Permanent File System

IP.com Disclosure Number: IPCOM000073583D
Original Publication Date: 2005-Feb-22
Included in the Prior Art Database: 2005-Feb-22
Document File: 3 page(s) / 63K

Publishing Venue

IBM

Abstract

Method and apparatus for integrating permanent and temporary file system architectures into a dual purpose file system architecture.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 52% of the total text.

Page 1 of 3

Method and Apparatus for an Integrated Temporary and Permanent File System

Disclosed is an invention for a file system architecture that allows temporary and permanent objects to be integrated into a single file system under a common interface. Applications using such a file system can take advantage of this integration to obtain increased flexibility and improved performance. Traditional file systems are either permanent or temporary. A permanent file system contains permanent objects and is designed to maintain critical data. A temporary file system contains temporary objects and is designed to be faster than a permanent file system. Permanent objects persist across a system reboot/initial program load (IPL) and temporary objects do not. This traditional file system architecture can increase application complexity, can reduce application performance and requires file system providers to maintain two unique file system architectures. The dual purpose file system architecture requires the following additions to be implemented beyond the traditional file system architecture:
(1) Method to provide user interfaces such as commands and/or application programming interfaces (APIs) to create permanent and temporary objects.
(2) Method to allow temporary objects to be linked into permanent directories.
(3) Method to allow permanent objects to be linked into temporary directories.
(4) Method to handle temporary object ghost directory entries.
(5) Method to minimize the number of lost permanent objects.

(1) Existing file system object creation user interfaces (i.e., mkdir, mkfifo, creat, etc.) are updated and/or new interfaces are provided to allow a user to indicate whether to create a permanent or a temporary object. In addition, the dual purpose file system architecture requires the following additions to object creation and linkage:

The directory entry for the object contains an indication of whether the object is


i.


ii.

permanent or temporary. For a temporary object, the directory entry also contains an IPL number to identify whether or not the current IPL created the object.

The object contains an indication of whether it is permanent or temporary. In

addition, a permanent object contains an indication of whether or not it is linked into a permanent directory.
(2) Linking temporary objects into permanent directories is unique and is not required to participate fully in normal file system input/output (IO) and journaling. Therefore, performance enhancements are made by bypassing unnecessary IO and journaling when a dual purpose file system manages permanent directory links to temporary objects. However, the file system needs to provide an additional method to handle temporary object ghost directory entries. Refer to (1) for additional link requirements and to (4) for ghost di...