Optical media size

I needed this, so I'm posting it here and also as a github gist

Optical Media

Write Once - Read Many (a.k.a. Read-Only)

The optical media industrial production systems work with a master media which is printed into the plastic discs using a thermal techinque transfering the zeroes (pits) and ones (lands) from the "negative" master to the final media, the types of media produced by this method are the following:

• CD-ROM
• DVD-ROM
• DVD-ROM Dual Layer
• HD DVD-ROM
• BD-ROM

One time write media

This kind of media may be recorded only once by using a laser which marks the pits and lands in the spiral groove of the disc on the polycarbonate layer, the data is formatted most of the times according to the ISO9660 standard described on [1], this kind of discs are refered with the following names:

• CD-R
• DVD+R
• DVD-R
• DVD+R Dual Layer
• DVD-R Dual Layer
• BD-R

ReWritable Media

The rewritable media, as its name implies, may be writed and erased many times, thanks to this feature a failed or incomplete burned disc may be erased and then reused rather than be disposed, the polycarbonate used can return to its normal state with the aid of a special laser beam. The designations for this media are as follows:

• CD-RW
• DVD+RW
• DVD-RW
• BD-RE

Credits

1. http://en.wikipedia.org/wiki/DVD
2. http://jesusnjim.com/using-computers/optical-drives/media-capacities.html

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