If by CDR you mean CD media, then it’s used for software distribution and storage of data. CDRW is similar bu also allows the ability to re-write on the media multiple times. With today’s larger programs some applications will come on DVD medias or are downloaded directly from the internet. I use CDR/DVD media for archiving my digital photos and other important documents. This make them easily portable over an external HD. IF you are not referring to CD media we need more clarification on your meaning of CDR. CDR could also be a Corel Draw file format.