Browse Prior Art Database

File Interface for Migrating Applications to Enhanced Persistent Storage Platforms

IP.com Disclosure Number: IPCOM000108521D
Original Publication Date: 1992-Jun-01
Included in the Prior Art Database: 2005-Mar-22
Document File: 2 page(s) / 103K

Publishing Venue

IBM

Related People

Christensen, J: AUTHOR [+3]

Abstract

Most existing software applications store persistent data in flat files. More powerful storage platforms (e.g., object bases) are being developed. Disclosed is an invention to permit old applications to transparently access new storage platforms to ease migration to new environments.

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This is the abbreviated version, containing approximately 52% of the total text.

File Interface for Migrating Applications to Enhanced Persistent Storage Platforms

       Most existing software applications store persistent data
in flat files.  More powerful storage platforms (e.g., object bases)
are being developed.  Disclosed is an invention to permit old
applications to transparently access new storage platforms to ease
migration to new environments.

      The migration to a new technology presents a chicken/egg
problem.  Applications will not be written to use a new technology
until that technology is well accepted; a technology will not be
accepted until it has a variety of applications written using it.  A
case in point is advanced storage paradigms, such as object bases.
Existing applications read and write flat files.  Records in these
files represent the persistent data of the application. Disclosed is
a technique to maintain this file system interface as a migration
tool for old applications to run in a new environment.

      The invention assumes the existence of an advanced storage
medium, such as an object base, and existing software designed to use
conventional file systems.  The invention consists of a redirector
module that is installed "in front" of the file system.  Existing
applications use their conventional file I/O and create/delete
operations. The redirector traps these operations and converts them
to operations on the advanced storage medium (such as methods on an
object).  Similarly, the redirector accepts messages from the
advanced storage medium and translates those to a set of file system
return codes (or similar status indications).  This generic module
can then be used to transparently port existing applications to the
new advanced storage medium.

      Consider, for example, the X window manager which uses the
".Xdefaults" file to store user customization information.  When an
x-application runs, it searches this file to collect all parameters
that relate to it.  To port a x-application to an object base would
require a rewrite of the existing file I/O routines to be (the
conceptually simpler) methods on user or customization objects.  The
disclosed redirection interface accepts the existing file I/O
commands from the old x-application and converts it to the
corresponding method calls.

      As a second example, consider another advan...