I have the premise that a cylinder and track are a 1:1 ratio. But what is confusing is taking a hard drive with 7 platters in use and then asking "how many tracks are on any 2 cylinders of this 7 platter hard drive" Is it 7 or would you double that to 7x2=14?

  • Sorry but your premise is just wrong. A track exists on a single surface. The only way cylinder and track are a 1:1 ratio is if your drive has just one surface in use. A cylinder consists of all of the tracks that are accessible without moving the heads. Note also that "surfaces" are not necessarily two times the number of platters: Not all drives use both surfaces of every platter. – Jamie Hanrahan Nov 30 '17 at 19:37
  • Your question title says “any two platters” but your question body says “any 2 cylinders”. – G-Man Says 'Reinstate Monica' Dec 1 '17 at 3:19

A track is a section of a cylinder. A drive with one platter and one head on a single surface of that track would have one track per cylinder. A drive with 7 platters would probably have a head on each surface of each , so that would make 14 tracks per cylinder.

So a drive with 7 platters and 14 heads has 28 tracks per two cylinders.

Keep in mind that cylinders aren't really a relevant concept in modern drives, as these drives use logical block addressing (LBA), where each logical sector is addressed by a single number, and the drive's firmware maps that to a physical track on a surface of a platter, but it is not possible to control or predict which surface.

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