| 摘要 |
<p>PURPOSE:To prevent destruction of data in a magnetic file device even in case of erroneous operation of a power switch by providing an electronic switch whose switching is controlled by a signal indicating that data is transferred. CONSTITUTION:If data is transferred when a user switches a manual operation switch 53 to the earth side to set it to the low level in the power supply state for the purpose of stopping the power supply, a data transfer request signal 31 goes to the high level, and inputs to a NAND circuit 52 go to the low level and the high level respectively, and therefore, the output of the NAND circuit 52 is in the low level as it is. At this time, a feed line 101 is connected to a power source 100 by the operation of a relay switch 51 as it is. When data transfer is terminated, the output of the NAND circuit 52 is inverted to the high level because a DMA controller sets the data transfer request signal to the low level. At this time, the relay switch 51 is operated to disconnect the feed line 101 from the power source 100. Consequently, the power source can be turned off when data transfer is not executed.</p> |
