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Local Shadowing of Remote File Directory Information

IP.com Disclosure Number: IPCOM000102129D
Original Publication Date: 1990-Oct-01
Included in the Prior Art Database: 2005-Mar-17
Document File: 3 page(s) / 132K

Publishing Venue

IBM

Related People

Crockett, DR: AUTHOR [+2]

Abstract

Local shadowing of remote directory information can significantly improve performance in systems that have the capability to maintain files remotely. Directory information is defined as the attributes of the elements (files) in a directory. The name, size, and last use date of the elements could be directory information, but the contents of the file would not. The improvement is derived from reduced message traffic due to fewer requests to the remote file system for directory information, and consolidating directory information updates with other requests for information from the remote file system. Storing the directory information in a format consistent with the local file system, and allowing the remote directories being shadowed to be selected by the local system can further improve performance.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 48% of the total text.

Local Shadowing of Remote File Directory Information

       Local shadowing of remote directory information can
significantly improve performance in systems that have the capability
to maintain files remotely.  Directory information is defined as the
attributes of the elements (files) in a directory.  The name, size,
and last use date of the elements could be directory information, but
the contents of the file would not.  The improvement is derived from
reduced message traffic due to fewer requests to the remote file
system for directory information, and consolidating directory
information updates with other requests for information from the
remote file system. Storing the directory information in a format
consistent with the local file system, and allowing the remote
directories being shadowed to be selected by the local system can
further improve performance.

      The shadowing process consists of three functions. First, the
local machine registers for shadowing, for a specific directory, with
the remote file system.  As a part of this, the remote file system
sends the current directory information and remembers that the local
system must process the directory update information sent by the
remote file system when the directory information changes.  Last,
when the local system decides it no longer desires the remote
directory shadowing, it discards its directory information and
notifies the remote file system it no longer requires directory
update information.

      The components of a network that would be able to make use of
this facility are shown in the figure.  The local system contains the
functions described in this article.  In the remote file system,
additional function would be required to provide the directory
information to the local system, in conjunction with providing its
remote file system support.  The local and remote functions required
for the system to operate could exist on both systems, allowing
either system to act as the remote file system or the local system,
the state being determined by the origin of the file system requests
and the location of the directories.

      The structure of the local system would be modified as
indicated in the figure.  The update information processor handles
translation of remote file system directory information into local
system data structures.  It does this for data received at
registration and for data received during later communications with
the remote file system. The shadowing services provide, to the local
operating system, interfaces to control the registration and
termination process.  The design is intended to minimize the
involvement of the local operating system, reducing modifications and
insulating the local operating system from the remote file system
data structures.

      Registration notifies the remote file system that the local
system wants to maintain a shadow directory for a specific remote
file system directory.  The loca...