Abstract: The system of the invention includes a board 2 mounted with a plurality of electronic components 1 and a controller 3, which has a faulty component detecting function and a hot swap function. Each of the electronic components 1 is mounted on the board 2 with electronic lock means 4A and 4B and also pressing means 5 and the board 2 is further mounted with a nonvolatile memory 6 in which a board-side unlock code is stored, which code is transmitted by the controller 3 to the electronic lock means 4A and 4B. The electronic lock means 4A and 4B are provided with a function to unlock a component if correspondence is detected between a board-side unlock code and a lock means-side unlock code.

Abstract: When an error occurs in a memory card of a computer system, error information having an error occurrence time, a number of a memory card in which the error has occurred, and an error status are sequentially stored as the error history information in a random access memory (RAM) connected to a system bus in the computer system. A number of errors of the memory card on which the error has occurred and an interval between the errors are calculated based on the error history information. When the calculation results deviate from each predetermined value, the memory card is deleted (e.g., disconnected from a memory board of the computer system) as having an intermittent fault or a high frequency of fault occurrence. During access to the memory, by referring to an address decode register, a memory card number is identified from the most-significant portion of the address.

Abstract: A multiprocessor system containing a plurality of processor boards each having at least one processor, a CPU (central processing unit) which has malfunctioned when the multiprocessor system boots up can be firmly isolated from a system bus. In this multiprocessor system, each of the plural processor boards includes a nonvolatile memory for storing therein an initial diagnosis result of each processor on this processor board. When a system boots up, a master processor in the respective processor boards is selected based upon the initial diagnosis result stored in the nonvolatile memory, and furthermore, a master processor for the entire system is selected from these selected master processors.