JPS551665A - Write-in protection unit - Google Patents

Abstract

PURPOSE:To prevent the double writing only on the partial area among the recording area of the rotary recording media, by outputting the data double write-in inhibit signal to the recording media, depending on the supply of the write-in mode display signal and the write-in inhibit signal given externally. CONSTITUTION:When the switch 5 is connected to the inhibit position, the signal at the switch 5 opnes the gate of the logical product gate circuit 7 via the logical sum gate circuit 6 and closes the inhibit gate circuit 9 while the output of the flip flop 3 indicates write-in inhibit state, so that the write-in data is not delivered to the write-in head 10. When program gives the write-in inhibit or write-in permission, it can be made by selecting the flip flop 4. For example, when write-in inhibit is desired by program, the flip flop 4 is set with the inhibit command in place of the switch 5, and when permission is desired, the flip flop 4 is reset with the permission command.