This document describes the file naming convention used in the exchange data archives. The naming convention was adopted in 1998 as an extension to the old, DOS-compatible naming convention.

The file naming convention uses the ISO 9660 convention which permits "name.ext" to be 30 characters, and uses the character set:

Notice that the alphabetic characters are upper case. The general expression for any file name is:

The square brackets [ ] enclose optional parameters, and the total length of the file name, including the "." (period), does not exceed 30 characters. The "_" (underscore) is used to separate optional parameters. The definitions of the component parameters are:

CC   =

two-character prefix for the file name (0-9, A-Z). Ideally, this will be a mnemonic code for the measurement, instrument, or subject of the file.

yyyy =

four digits specifying year (i.e. 1997, 2001, etc.).

MM   =

two digits specifying month number (01-12).

dd   =

two digits specifying day number (01-31).

hh   =

optional two digits specifying hour (00-23).

mm   =

optional two digits specifying minutes (00-59).

ss   =

optional two digits specifying seconds (00-59).

I    =

one or more characters used to further specify the contents of the file or the subject of an image. This parameter is usually optional (in the sense that we can decide to use it or not), but there are two cases where it is required.

If a data file is one volume of a multi-volume dataset then a volume counter "Vn" (i.e. V1, V2, V3, etc.), must appear at the end of the "I" identifier, and be separated by an "_" from the rest of the identifier.

• The volume number (the "n" in "Vn") must match the volume number (IVOL) in the sixth line of the file header.
• The number of digits used in each volume number must be the same (V1,V2,V3,..., or V01,V02,V03,..., etc.).
• If "Vn" is omitted from the file name then volume number one of a one-volume dataset is implied.

If the contents of the file pertain to a second or third aircraft launch on the indicated date then a launch counter "Ln" (i.e. L2, L3, etc.) must appear at the end of the "I" identifier, but before a volume counter, and be separated by an "_" from the rest of the identifier. If "Ln" is omitted from the file name then launch number one is implied.

P    =

two or more characters to identify the measurement platform, source, or association of the data (for data files), or image type (for image files).

Some things to notice are:

• Dates and times in file names are always UTC.
• In general, the date and time in the file name give the date/time at which the data within the file begin (data files), or date/time at which the image applies (image files). For aircraft data files, the date always refers to the UT date of launch, and further specification of time in those file names is discouraged.
• There can be two, four, or six digits following the first "_", which represent hh, hhmm, or hhmmss.
• If the "I" identifier is used without a time, then it is separated from the date by two "_" (e.g. CCyyyyMMdd__I.P).
• File name codes are constructed from the constant parts of the file names and used as a shorthand way to reference a particular type of file. Usually the file name code will be CC.P, but it can be CC__c.P, where "c" represents the constant part of the "I" identifier ("Ln" and "Vn" are variable parts of "I").
• For any given experiment, all file name codes must be unique. If two or more file names use the same prefix "CC" and extension "P" then all of those names must also include a "c" identifier, and those identifiers must be unique for each type of file.
• File catalogs (filetable.lis and imagetable.lis) will be provided for each experiment to link file name codes, and therefore file names, with the contents or subject of each type of file.

The file name extension, P, is used to identify the measurement platform, source, or association of the information within a data file, or the type of image file. A list of the file name extensions which are currently being used in the archives is given below. Others will be defined as needed.

Some examples of file name codes, file names, and explanations of the meaning of the file names are given below to illustrate the construction of file codes and file names.