| 360 / | HD | DYNAMIC MAGNETIC INFORMATION STORAGE OR RETRIEVAL |
|
| 69 | DF | AUTOMATIC CONTROL OF A RECORDER MECHANISM {3} |
| 75 | DF | .~ Controlling the head {3} |
| 77.01 | DF | .~.~ Track centering {2} |
| 77.02 |  | .~.~.~ Rotary carrier {5} |
| 77.03 | DF | .~.~.~.~> By nonmagnetic sensing (e.g., optical, capacitive) |
| 77.04 | DF | .~.~.~.~> By memory storage of repeatable error or correction |
| 77.05 | DF | .~.~.~.~> By servo signal component from carrier surface separate from information signal bearing surface |
| 77.06 | DF | .~.~.~.~> Reproduced data signal used for tracking |
| 77.07 | DF | .~.~.~.~> By tracking signal recorded on or immediately beneath surface {2} |