The non-qc'ed data files are referred to as "t" files.  Their names begin with t and is followed by the numerical representation of the year, month, day and hour (e.g. 1998021212 for Feb. 12, 1998 12Z).  Records on these files are actually followed by newline characters, making them viewable by text editors.  These "t" files contain many different types of data such as surface land, radiosonde, etc.  There are baby "t" files that contain only one type of data and are identified by a two character suffix (see table 1 for details).

Files containing qc'ed data for MVOI input are ASCII, but do not have newline characters.  This allows for a more efficient stream input.  Unfortunately, they do not lend themselves to text editors.  Their names have a three upper-case character data type indentifier (see table 1), followed by 6 digits.  The first digits represent the 24-hour time, and the last four show the continuation sequence.