
Fundamentals of Optical Storage 65
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3.7 Optical Disc Storage Development
Capacity and throughput for optical storage will continue to improve, though it
occurs more slowly than for magnetic storage. Optical disc capacity increases not
incrementally, as is the case for magnetic disc and tape, but in distinct leaps often
separated by years (for example, 650 MB audio CD to 4.7 GB video DVD to 25 GB
high defi nition blue laser discs). Moreover, optical media are removable, which in itself
mandates more conservative capacity targets.
Throughput for optical storage devices, as defi ned by data rate and access time, is well
behind ...