Posts Tagged ‘media storage cabinet’

Short history of the CD/DVD

September 5, 2011

Short history of the Compact Disc
The invention of the Compact Disc has had a large impact on both music and computing in the last 20 years. Invented in 1979 as a joint project between Sony and Phillips to counter the self-destructive nature of consumer audio playback (such as tapes and records that could only be played so many times before the recording degraded significantly) by switching to a resilient digital format.

The CD was also designed to store standard computer data, as in 1985 the first CD drives for computers were released; massive, bulky, and expensive, it was not until the mid-90s that they really took off, driven almost solely by video games and large multimedia applications.

In 1990, Sony and Phillips went back to the drawing table, and then came out with the CD-R, a record-once medium. Yet again, the first CD burners were large, expensive, and bulky, but by the late 90s having a CD burner was the new ‘in’.

The first few generations of CD media, designed by Taiyo Yuden (a company who I respect, and buy all my archival quality media from), actually kind of sucked; it wasn’t until around 2000 that companies started producing very high end media.

CDs and DVDs store individual bits (encoded in various ways depending on the media) with spots of reflective and non-reflective areas. This method is called ‘pits and lands’, where pits ‘absorb’ light (ie, are ‘off’ bits) and lands ‘reflect’ light (ie, are ‘on’ bits).

With pressed media, the pressing method causes pits to reflect the laser’s light away from the sensor, and the lands to reflect it back at the sensor. With burned media, a high energy laser causes spots of organic dye to go opaque and obscure the reflective surface for the pits, leaving the organic dye for lands alone.

Short history of the DVD
While burning was becoming popular in the late 90s, so was playing high quality video on DVDs. Storing almost 7 times the data of a 700MB CD (or almost 13 in the case of dual layer DVDs), allowed companies to store massive amounts of data on one disc, leading to the movie industry to drop VHS tapes and the video game industry to drop CDs.

In 1995, the first DVD specification was ratified by over a dozen companies including Sony and Phillips, as well as Thompson, Pioneer, and Mitsubishi. By 2000, at least half the homes in the US and Japan had DVD players.

So, obviously, the next step was to produce burnable DVDs. Two separate, and incompatible, efforts took hold. The first one, Pioneer’s DVD-R (pronounced ‘DVD dash R’) was released in 1997, using different data storage methods than pressed DVDs (appearing to be more like CD-R than DVD), a poor error correction scheme, and the ‘wobble’ laser tracking system of DVD-R is inadequate for the job.

The second effort, lead by the DVD+RW Alliance (headed by Sony, Phillips, Mitsubishi, and Thompson) was released in 2002, as an alternative to the poorly implemented DVD-R. DVD+R uses a superior ‘wobble’ laser tracking system, a far better error correction method, and the media quality itself is typically higher.