STANDARDS CHANGE REQUEST ======================== Purpose: To make directory name specifications consistent. Date: 2003-04-04 Submitted by: T. King Working Group: TBD Edit: 2005-06-10 - Updates by E. Rye in response to standards telecon on 2005-06-08 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 attain internal consistency with regard to the ISO 9660 Level 2 standards for directory and file names. Section 8.2 Formation of Directory Names ---------------------------------------- Change point 2 to read: It is recommended that directory names not exceed 8 characters in length, in compliance with the ISO 9660 Level 1 standard. Even when there are compelling reasons to relax this standard, directory names must still comply with the ISO 9660 Level 2 standard and not exceed 31 characters in length. Section 8.3 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. Chapter 10 File Specification and Naming ---------------------------------------- Change the third paragraph to read: When there are compelling reasons to relax the 8.3 file name standard, the ISO 9660 Level 2 specification with respect to file names may be used, subject to the restrictions listed in Section 10.1.2. Section 10.1.1 ISO 9660 Level 1 Specification --------------------------------------------- Change the first paragraph by removing the final sentence, which reads: Since PDS archive volumes are designed to be read on many platforms, including PCs, these restrictions are necessary. Section 10.1.2 ISO 9660 Level 2 Specification --------------------------------------------- Change the first paragraph to read: The PDS use of ISO 9660 Level 2 file names adheres to all the above restrictions, with the exception that the base name may be up to 27 characters long (total file name length not to exceed 31 characters). Thus, this format is sometimes referred to as the "27.3" format. Change the fourth paragraph to read: Note that only the file and directory name specifications for Level 2 may be used in PDS archive volumes. All other Level 2 extensions are prohibited. Impact Statement ================ The following represents the set of impacts to the PDS which will be affected by changes. Operational Impacts ------------------- This is a clarification change and does not affect any existing products in the PDS archive. It will make adherance to our standards easier for data providers. Software Tools -------------- None. An assessment does need to be done to determine if validation tools check for file/directory name limitations. Changes will need to be made if checks are not consistent.