Many people mistakenly think that the DVD-ROM discs are the same as recordable DVD.  DVD-ROM discs are “pressed” using a special stamper that puts an imprint into a clear polycarbonate layer with a layer of aluminum or silver in the middle the (reflective layer) and then another layer of polycarbonate.  Stamped discs are more cost effective in larger runs (10,000) and single title production.  Recordable DVD provides the flexibility of one off disc production (marketing, training, file distribution) and larger disc runs that fall below the cost effectiveness of stamped discs.  The equipment for stamping costs hundreds of thousands of dollars and DVD duplicators can cost as low as $200.

Recordable blank DVD discs have evolved from pre-authoring media (version 1), authoring (V2.0), DVD-R and DVD+R.  Starting capacity was 3.95 GB.  Authoring media actually uses a different wavelength then General Purpose (DVD-R and DVD+R for General Purpose) for recording.  They can be read by just about any DVD reader but recording is a different matter. Another format that was supposed to revolutionize optical discs is DVD-RAM.  DVD-RAM is similar to rewritable media but with a different file format.  Instead of recording in a ‘track’ it is sector based like a hard drive.

In today’s world the majority of DVD media used is General Purpose. DVD-R, DVD+R, DVD-RW and DVD+RW.  Dual layer DVD comes in DVD+R and DVD-R.  DVD plus R is the most compatible and the largest market share.  DVD-R was developed by Pioneer and released in 1997 under the authoring media format.  DVD+R was developed by a consortium that includes Sony, Ricoh, HP, Dell and others. It was developed to compete against DVD-R.  DVD+R has been promoted by the consortium through different computer businesses like Dell. For a time (before dual format drives) some computers had ether a DVD+R recorder or a DVD-D recorder and many people had no idea which drive was installed.   DVD-R has always been less expensive then DVD+R and has no advantage over DVD-R.  That is unless your computer you bought had a drive in it that required more expensive media that the manufacturer promoted. 

DVD+R DL provides 8.5 GB storage using a dual layer configuration on a single side of blank DVD media. Surprisingly the DVD-R DL version has not been very successful and has experienced a lot of compatibility issues.  DVD+R DL or Dual Layer offers a far greater compatibility although it only recently became a real officially recognized format.  DVD+R DL has been a informal format that actually became more successful then the Pioneer DVD-R DL version.