Portable means easy to carry round,
Optical means uses light to make it work.
So optical media could be portable.
Optical disk
Linux has drivers built in already for portable media. Many times with Windows, you have to download drivers from 3rd party sources.
Optical Disk
The angle of incidence.The difference in the optical densities of the media.
The CD and the DVD.
Optical disc
what is the difference between synthetic and non-synthrtic media
Portable media player was created in 2002.
The flash media does not last as long as the optical media. Flash media is about the moment and will not be supported for as long.
optical
SIC 3695 covers making optical recording media
index of refraction ( or refractive index)