NAME:
  reconcksum
 PURPOSE:   (one line only)
  Generate or refresh video data checksums
 DESCRIPTION:
 CATEGORY:
  Database
 CALLING SEQUENCE:
  reconcksum
 INPUTS:
 OPTIONAL INPUT PARAMETERS:
 KEYWORD INPUT PARAMETERS:
  MAXTODO - maximum number of updates to perform
 OUTPUTS:
 KEYWORD OUTPUT PARAMETERS:
 COMMON BLOCKS:
 SIDE EFFECTS:
 RESTRICTIONS:
 PROCEDURE:
 MODIFICATION HISTORY:
  2016/03/10, Written by Marc W. Buie, Southwest Research Institute
  2020/12/30, MWB, added more debug output on bad file mode error