That makes it possible not just to skip to any point of a taped show in a split-second, but also to rewind live television: because hard disks are so fast, they can tape and play back at the same time.

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But before we go there, a quick rewind is in order to explain why this research was conducted.

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Its DC motor means there's no regenerative braking, but he claims it's cheaper and allows owners to rewind the armature or upgrade the brushes.

ENGADGET