| 摘要 |
PURPOSE:To realize the reading of information even when one of the two readers for the information on both surfaces is damaged, by giving the control to both the turning direction of a disk and the shifting direction of the number of tracks in accordance with the shift of the track number according to the changeover of a switch. CONSTITUTION:In case one of the two readers for the information on both surfaces of a flexible disk is faulty, the disk is inserted with its upper and lower surfaces reversed to each other and a switch 1 of a switch part 200 is switched to set an FF2. As a result, a motor 5 turns adversely via drive part 300, and a disk 7 is turned in the direction opposite to the normal direction. At the same time, an FF7 is set to open an AND gate 8. And a timer counter 6 counts 4 bits, etc. to reset the FF7. On the other hand, an inverse signal difference from a normal one is delivered in the period during which the FF7 if set by a direction selector 10. Then the shift corresponding to the number of e.g. 4 tracks is controlled in the opposite direction. Thus the information can be read by the other nondefective reader. |
