This is the main window of CD/DVD Diagnostic where you can see information about the DVD contained in the DVD device. The first window that appears is the Disc Examination Information that tells you the writing method of the current DVD 

The Analysis Process from the Tools menu displays the Results of Analysis window that shows you information about the file systems contained on the disc, the occupied sectors and the UDF file system information 

Here you can see how CD/DVD Diagnostic performs Disc Readability test that you should run without accessing other applications at the same time 

In the CD/DVD Hardware Information window you are being displayed information about the Device Name, Revision date, Supported bar code reading, supported audio play and many other information 

In the User Preferences windwo you can set general Options as well as options about the Readability test Device Settings and Disc Memory