Cylinder – Combination of the Same Tracks on Different Discs [MiniTool Wiki]
Cylinder refers to the combination of the same tracks on different discs. The number of turns of concentric circles ( track ) on disc is the number of cylinder. These tracks have a same magnetic filed rotating direction. If there is a dead pixel on one track, the track will be abandoned, because this track can't constitute a path. This is just like the situation where a piece of wire is broken down in series circuit.
Tip: Have you heard cylinder alignment on hard disk partition ? This way is used in older OS versions like Windows XP and Windows Vista . MiniTool Partition Wizard enables you to align to Cylinder when creating a partition .