| 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 | DF | .~.~.~ Rotary carrier {5} |
| 77.07 | DF | .~.~.~.~ By tracking signal recorded on or immediately beneath surface {2} |
| 77.08 | ![]() | .~.~.~.~.~ Distinct servo sector |