The evolution of the DVD-ROM drive is much like the CD-ROM drive in many aspects. Those old enough to remember the first single speed CD-ROM drive will also remember how buggy it was and how slow the thing was. It was also quite an expensive "beast". The single speed DVD-ROM drive was a little better, but still suffered from being too expensive for the common Job Public. And as you may have guessed, the "speed rating" of DVD-ROM drives is different. Roughly speaking a "1X" speed rating for a DVD-ROM is equaivalent to a "6X" speed rating for a CD-ROM drive. The 4th generation DVD-ROM drives are rated at around "10-16X", which means they can access CD-ROMs at about "50-60X" (but in actual pratice, they are only around 40-45X), not too bad! And yes, DVD-ROM drives can read CD-ROMs too (and all its cousins, like VCD, CDG, Music CDs...). Considering many computer suppliers don't even stock CD-ROM drives anymore, and that DVD-ROM drives are getting cheaper and cheaper (price wise, not quality), there really isn't any good reason not to have a DVD-ROM drive as a standard item in your next computer purchase.
Generation Gap
As mentioned before, DVD-ROMs have already reached the 4th Generation stage. The only real difference between 2nd, 3rd and 4th Gen. drives is the speed rating, and the region control (more about that later on) - other than that, they're pratically the same. However, 1st Gen. drives were pretty lame at compatibility, having trouble with dual-layed DVDs, with most DVD-Rs and also CD-R reading. Personally, I have a 3rd and 4th Generation Pioneer drive, which is fast and reliable, and has some neat features too.
