STANDARDS CHANGE REQUEST
                           ========================

      Purpose: To make directory name specifications consistent.
         Date: 2003-04-04
 Submitted by: T. King
Working Group: TBD


Background
==========
The current standards permit the use of ISO 9660 Level 2 specifications
for directory names, but the section which describes allowed directory names
is inconsistent with this standard.


Current Urgency
===============
This is a clarification of the documentation which is important
for those who are new to PDS such as new missions and providers.


Recommendations
===============
The following actions are recommended:

  1. Modify the current version of the PDS Standards Reference to make
     it internally consistent.
 
Changes to the Standards Reference
==================================
  The following are the set of changes to the PDS Standards Reference required
  to support the use of relative paths in pointer references to external files.

  Section 18.3 Path Formation Standard
  -------------------------------------
  Change the first two sentences in the first paragraph to:  
	The PDS standard for path names is based on Level 2 of the ISO 9660 international standard. A
	pathname may consist of up to eight directory levels. Each directory name is limited to 31
	characters; the forward-slash character ("/") is used as the separator in path names.

  Section 10.1.2 ISO 9660 Level 2 Specification
  ---------------------------------------------
  Change the first paragraph to:
	The PDS use of ISO 9660 Level 2 file and directory names adheres to all the above restrictions,
	with one exception: the base name of files may be up to 27 characters long (which is followed 
	by a literal "." and an extension of 3 characters). Total file name length may not exceed 31 
	characters. Thus, this format is sometimes referred to as the "27.3" format. Directory names
	do not have extensions and are limited to 31 characters in length.
	
Impact Statement
================

  The following represents the set of impacts to the PDS which will be
  affected by changes.

  Operational Impacts
  -------------------
  None. This is a clarification change and does not affect any existing products in the 
  PDS archive.
  
  Software Tools
  --------------
  None. An assessment does need to be done to determine if validation tools check the
  for file/directory name limitations. Changes will need to be made if checks are not
  consistent.