An excerpt from 1UP.com is below. More can be found in the links area.
As the 16-bit wars geared up, Nintendo and Sega both realized that the next generation meant more buttons. Sega's Genesis controller added two more buttons back onto the actual pad and not the console: one of them was a Start button, but the other was an additional button to be used in gameplay. Not to be outdone, Nintendo added four buttons to the SNES controller: two extra face buttons, arranged in the now-familiar diamond shape, and "shoulder" buttons labeled L and R that sat atop the controller and could be pressed by the index fingers.
As it turns out, neither of these standard controllers were the optimum solution for what turned out to be the hit game of the generation: Street Fighter II. While the Super Nintendo controller had exactly enough buttons for the game's array of martial arts moves, the buttons weren't in the right three-by-two configuration. Meanwhile, the Genesis controller didn't have enough. Sega responded by releasing a six-button pad with a three-by-two button layout on the controller's face, which became quite popular.
Entertainment
The entertainment industry has grown and evolved over the years with music and cinema taking a new form through the ages and so have the technologies that fuel it. Gone are the days of eight songs on a cassette and VCR players with merely two hours of entertainment recorded on a single video cassette. With the advent of computers came digital data storage and hence the birth of DVD/CDs.
Quiet a step back in matters of physical form as these new generation audio/video storage devices hold an uncanny resemblance to the records that preceded the cassette generation. DVDs and CDs today are an everyday household entertainment storage device which has come a long way since the first records and cassettes were distributed commercially.
Notable advantages of DVD/CDs have to begin with the amount of storage space available. These days its possible to burn multiple movies on a single DVD and as far as audio goes if its in a highly compressed format such as .mp3 a single CD can accommodate multiple music albums. These discs are easy to handle, light and portable with no moving devices unlike the tape generation however they are delicate and a scratch on the DVD/CD surface could cause a disruption in the information being read by the player.
DVD/CDs were initially invented to provide high quality audio/video data to a user with the ability to regulate its production however this soon fizzled away with daily household computers gaining the ability to burn data in such formats. The race to curb piracy through such means has not hit a roadblock and DVD/CDs keep evolving with newer encryption technologies in a bid to curb unchecked replication of data spawning newer technologies like Blu-ray discs which seems to be yet another milestone on an unending road of innovation.
