Browse Prior Art Database

Implicit Mapping of File Data

IP.com Disclosure Number: IPCOM000115385D
Original Publication Date: 1995-Apr-01
Included in the Prior Art Database: 2005-Mar-30
Document File: 2 page(s) / 36K

Publishing Venue

IBM

Related People

Copeland, G: AUTHOR [+3]

Abstract

Disclosed is a method for providing the benefits of mapping files without requiring changes to existing applications. An application continues to use the standard file system Open, Read, Write, and Close commands. This method of implicit mapping allows an application to read and write cached data locally, without going to a file server. Once a file is mapped, many accesses can take place without sending a message to the file server.

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Implicit Mapping of File Data

      Disclosed is a method for providing the benefits of mapping
files without requiring changes to existing applications.  An
application continues to use the standard file system Open, Read,
Write, and Close commands.  This method of implicit mapping allows an
application to read and write cached data locally, without going to a
file server.  Once a file is mapped, many accesses can take place
without sending a message to the file server.

      The Figure is a block diagram providing an overview of using
the implicit mapping process, as divided into an application task 1
and a file server task 2.  The application program 3 issues
personality-dependent file system operations, such as DosRead.  Such
requests are handled by the personality emulation library 4, which
translates them into personality-neutral file server operations, such
as FS_Read.  Next, the file server library 5 services the requests
locally, after ensuring that the correct file windows are mapped into
its address space.  If the correct file windows are not mapped into
its address space, file server library 5 sends the messages to a file
server 6.

      The code in the file server library 5 does the actual mapping
of the file, providing the benefits of mapped files without requiring
changes to the application, while using standard file system APIs
(Application Program Interfaces).