| 摘要 |
<p>PURPOSE:To provide a technique, which is capable of preventing the erroneous insertion of a package when it is inserted again, without changing the structure of a conventional package, and with only the addition of a simple circuit. CONSTITUTION:A shelf 2, on which a plurality of packages 1 to be used in an electronic data processing system are mountable, is provided with a plurality of displays 4, each of which is disposed above each insertion port 3 for the package 1, and a memory means 5 in which the status of the inserted package 1 is stored. This memory means stores, as the original state, the state in which the package 1 is inserted, and switches the status of the display 4 when the original state is changed or when the package 1 is inserted into an unoccupied insertion port 3.</p> |
