Transcription: Let's look at what we just saw in slow motion. When a brief pulse of electricity is sent to the read-write head, it flips on a tiny electromagnet for a fraction of a second. The magnet creates a field, which changes the polarity of a tiny, tiny portion of the metal particles which coat each platter surface. A pattern series of these tiny charged up areas on the disk represents a single bit of data in the binary number system used by computers. Now if the current is sent one way through the read-write the area is polarized in one direction. If the current is sent in the opposite direction, the ...
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