The INDEX directory contains 2 indices for this volume : INDEX.TAB and 
BROWSE_INDEX.TAB

Accompanying each index files is a PDS label (INDEX.LBL and BROWSE_INDEX.LBL).

The *.TAB files are ASCII files.  Each line (or record) in the .TAB-files
contains information about a single data file in the data or browse archive 
volume. Each line in a *.TAB file is made up of comma-delimited fixed-length 
fields.

Users of the SOIR archive can make use of the BROWSE directory to have a quick
look into the available data products. The structure and naming conventions 
for the BROWSE directory are completely identical to that of the DATA 
directory.