Interface question

[doctor-z]

Many programs like DVDInfoPro refer "Connection Interface" for every optical drive, and it has the value SCSI or ATAPI (IDE in some other programs). I also found this enumeration:

enum Interface {
 SCSI,
  IDE,
  OTHER
 };

 

and I want to ask where is this enumeration used. I checked inquiry, checked page 2A but nothing found. Only feature 001h is using something like this enumeration but there the enumeration is different.