XTE Data Finder
                             ===============

NAME
    xdf -- The GUI XTE data finder
    
    
USAGE
    xdf
    
    
DESCRIPTION

    XDF is a tool to navigate the XTE FITS Database (XFDB).  Its
    purpose is to select FITS data tables based on selection criteria
    provided by the user.

    The user interface consists of six 'Selection Boxes', one text
    widget, and various action buttons.


  Selection Boxes
  ---------------

    All boxes contain four or five buttons that operate on them:

       Help:  Pop up help window for Selection Box.
       All:   Select all items in the Selection Box.
       None:  De-select all items in the Selection Box.
       Reset: Reset contents of Selection Box to default value.
       Edit:  (for some) Edit the contents of the Selection Box.

    The boxes are:

       1. Source List
          >>Created by the user.

          Allows the user to specify particular source names.
          Wildcard characters are accepted.  No selection means 'no
          constraints'.

       2. Time Range List
          >>Created by the user.

          The user may specify certain time ranges in the format:
              yyyyMMMdd at hh:mm:ss.s to yyyyMMMdd at hh:mm:ss.s
          For instance:
              1995Apr07 at 12:00:00 to 1995JUN30 at 22:23:24
          No selection means 'no constraints'.

       3. Subsystem List
          >>User selects from a fixed list.

          Allows the user to select one or more from the list of 15
          XTE subsystems. No selection means 'all'.

       4. Observation List
          >>Created by action button.

          Observations are selected from the database on the basis of
          the selection criteria currently set by the Source List and
          the Time Range List. The user _has_ to select one or more
          items from this list.

       5. AppId/Configuration List
          >>Created by action button.

          AppIds (spacecraft data sources) and, for the science data,
          data modes and configurations are selected from the database
          on the basis of the selection criteria currently set by the
          Observation List and the Subsystem List.  The user _has_ to
          select one or more items from this list.

       6. FITS File List
          >>Created by action button.

          FITS data table files are selected from the database on the
          basis of the selection criteria currently set by the
          Observation List, the Subsystem List, the
          AppId/Configuration List, and the Time Range List.  Files
          may be selected and their names saved in the file
          ./fits_files.xdf.  If none are selected, the Save FileList
          action will save all names in the list.  This is, at the
          moment, the end product of XDF.


  Directions for Use
  ------------------

    1. Set the path to the top of the database.

    2. Set source name selection (if any).

    3. Set time range selection (if any).

    4. Press action button to make Observation List.

    5. Select observations.

    6. Set subsystem selection (if any).

    7. Press action button to make AppId/Configuration List

    8. Select AppId/Configuration combinations.

    9. Adjust observation, time range, subsystem selection, if
       desired.  Only additional restrictions will have effect!

    10.Press action button to make File List.

    11.Select files and press action button to save their names.


  The Button Bar
  --------------

    Reset
       Reset the contents of all boxes to their default values.

    Save
       Save the current contents and state of all boxes.

    Restore
       Restore the contents and state of all boxes as it was last
       saved.

    Make ObsList
       Construct the list of observations on the basis of source
       names and time ranges.

    Make AppIdConfigList
       Construct the list of AppIds and Configurations on the basis
       of the selected observations and subsystems.

    Make FileList
       Construct the list of FITS data files on the basis of the
       selected observations, subsystems, AppId/configurations
       combinations, and time ranges.

    Save FileList
       Save the names of selected files (all if none selected) in
       the file ./fits_files.xdf.

    Help
       Display this text.

    Path
       The (file system) path to the XFDB Master Index that is to
       be used.

    Quit
       Exit XDF.  The contents and state of all boxes is saved
       before exiting.  This is automatically restored at the next
       execution.