***** File INDXINFO.TXT                                                       
                                                                              
                                                                              
                       Index File Information                                 
                                                                              
                                                                              
                                                                              
     This file contains a description of the index files created for the L-SP 
Discipline CD-ROMs.  There are twenty five files in the INDEX directory       
(besides this file), all relating to this particular disc.  Most are intended 
for creating a database to guide the user in selecting files of interest.     
                                                                              
                                                                              
     The CALIB.* files contain the names of files containing calibration data,
and the names of the data files which they calibrate.  The CDSTRUCT.* files   
contain a full list of all header and data files on this disc, along with file
sizes, allocations and physical block numbers.  This database may be of use   
for those writing direct access routines.  The EPHEM.* files contain the comet
ephemeris spanning the dates on this disc.  It is a delimited form of the file
EPHEM.TAB in the EPHEM subdirectory.  The NETLARGE.* files contain the full   
set of FITS keywords specific to the Large-Scale Phenomena Discipline.  The   
values are taken from the original FITS headers for the files included on this
disc.  The PATHTABL.* files give the full directory path to the data files on 
the disc. Unlike the CDSTRUCT database (which contains entries for all files),
only the names of the data files are in the PATHTABL database.  This database 
will assist the user in determining which subdirectory contains the data of   
interest, as well as assisting in constructing a fully-qualified file name for
the data files.   On the disc HAL_0018, a special PATHTABL is located in the  
SUMMARY directory.   It contains the full directory path to all data files    
on discs HAL_0001 through HAL_0018.                                           
                                                                              
     There are four types of files associated with each index, distinguished  
by the extensions on the file names.  The four types of files are:            
                                                                              
        *.DBF - These are dBASE III+ compatible database files.  They do not  
                contain any data records, only the structure of the           
                corresponding database.  The data records may be appended from
                the data tables (in the .IDX files).  Many database management
                systems can import databases from .DBF files.                 
                                                                              
        *.IDX - These files contain the actual data records from each table.  
                They are delimited tables.  Numeric fields are delimited by   
                commas (,) and ASCII text fields are contained in quotes (")  
                and also delimited with commas.  Each line ends with the      
                characters <CR><LF> (ASCII 13 and 10 respectively).  For each 
                disc, fields in the tables are fixed width and the total width
                for each table follows: CALIB, 70 bytes; CDSTRUCT, 74 bytes;  
                EPHEM, 108 bytes; LSPNOBS, 258 bytes; NETLARGE, 787 bytes;    
                and PATHTABL, 80 bytes.   The summary PATHTABL on disc        
                HAL_0018 is 131 bytes.  These files may be appended to the    
                end of an empty database structure to create the full index   
                database.                                                     
                                                                              
        *.STR - These are "structure" files.  They contain information, in    
                delimited format, on the number, names and widths of the      
                fields in each database.  They have been provided as ASCII    
                files of fixed length (80 bytes) to document the structure    
                of each table.                                                
                                                                              
        *.HDR - These are FITS header files, containing both the standard and 
                extension headers.  The files are not text files, although    
                they contain only ASCII characters.  There are no delimiters, 
                and both the standard and extension headers are padded to     
                lengths which are multiples of 2880 bytes.  In order to create
                a fully compatible FITS byte stream, simply concatenate the   
                header file with the corresponding .IDX file and pad to fill  
                out the byte stream in multiples of 2880.                     
                                                                              
     In order to create a database from dBASE III with these files, issue the 
following commands at the "." (dot) prompt:                                   
                                                                              
     . use <filename>                                                         
     . append from <filename>.idx delimited                                   
                                                                              
where <filename> is one of CALIB, CDSTRUCT, EPHEM, LSPNOBS, NETLARGE or       
PATHTABL.  Most database programs can import dBASE III compatible files.  In  
order to use another database program to manage the index tables, you will    
need to import the (empty) index from the appropriate .DBF file, then append  
the data from the corresponding .IDX file.                                    
                                                                              
     There is one additional file (STRUCT.DBF) in this subdirectory. This is  
the database used to create all the other databases. It consists of 4 fields, 
FIELD_NAME, FIELD_TYPE, FIELD_LEN and FIELD_DEC, which document the structure 
of the index tables. When the appropriate .STR file is appended to this       
structure database, dBASE III+ can create the corresponding index database.