MEMORY BOARD

PURPOSE:To test respective memory boards approximately in parallel by providing each of plural memory boards with a check circuit which tests all memories and starting this check circuit by a CPU. CONSTITUTION:A memory element 12 is arranged on a memory board 1, and respective signal lines of this memory element 12 are connected to the external through a buffer 13. A memory check circuit 11 which checks the memory element 12 is connected approximately in parallel with respective signal lines through an output buffer 14. This memory board 1 is accessed from the CPU through a memory controller.