• The only difference between the two formats is the way the DVD drive determines the position of the laser on the disc. DVD-R discs are read by the DVD drive through special grooves on the disc known as land prepits, whereas DVD+R measures a disc's wobble frequency.
   
• A consumer can also purchase a "dual-DVD" drive that supports both the DVD-R and DVD+R format, typically known as DVD±R.
   
• DVD-ROM drives can read CD-ROM disks, so if you have a DVD-ROM drive, you don't need an extra CD-ROM drive. Also, the x-factor for DVD drives refers to a higher transfer rate: 1x DVD-ROM drives transfer data at the rate of a 9x CD-ROM drive.
   
• Most complete systems with DVD-ROM drives will ship with 12x or 16x DVD-ROM drives today. DVD-ROM drives are dirt cheap today, so don't even bother with plain CD-ROM drives unless you have no choice.
   
• In 2002, Sony and Phillips introduced the DVD+R format. All DVD+R formats are compatible with each other. DVD+R has the same capacity as a DVD-R, and DVD+RW works exactly as a DVD-RW. This format also offers DVD+RW DL.
   
• The DL stands for dual layer, a technology which allows a single disc to hold up to 8.5 GB of information. The DVD-RAM offers more storage capacity, but it requires a specialized DVD drive which is more expensive.
   
• The DVD-RAM format enables the disc to be re-written with the DVD drive up to 100,000 times as opposed to only 1,000 times or so for an average DVD-RW. It can be two-sided, enabling as much as 9.74 GB on a single DVD-RAM disc. This disc is best for users with mass portable storage needs.

A "dual DVD" drive or DVD±R with DVD-RAM is very versatile, as it reads all formats of DVD technology and is capable of writing to all forms. Typically, a user will achieve speeds of 16x write for DVD+/- , 8x write for DVD+ DL and 5x write for DVD-RAM, as well as the capacity to write regular CD-R at 48x with this type of DVD drive. This ensures any format of disc will work when using the dual DVD drive.