| 360 / | HD | DYNAMIC MAGNETIC INFORMATION STORAGE OR RETRIEVAL |
| 69 | DF | AUTOMATIC CONTROL OF A RECORDER MECHANISM {3} |
| 71 | DF | .~ Controlling the record {3} |
| 72.1 | ![]() | .~.~ Locating specific areas {2} |
| 72.2 | DF | .~.~.~> Responsive to recorded address |
| 72.3 | DF | .~.~.~> Responsive to tape transport |