CORRECTING AND PROCESSING SYSTEM FOR CONTENTS OF SYSTEM ROM

摘要

PURPOSE:To facilitate an easy correction of a bug while keeping an ROM storing the system program including the bug kept as it is by using an ROM or RAM for patch in addition to a system ROM or RAM. CONSTITUTION:A CPU, a system RAM2 and a system ROM6 are provided to a system. The instruction and data of the system are stored in the ROM6, and the contents of the ROM6 are developed to the RAM2 under the control of the CPU1. The information is stored in a patch ROM8 to correct the contents of the ROM6 developed to the RAM2. When this system is actuated, the CPU1 performs the processing so as to develop the contents of the ROM6 to the RAM2. At the same time, the instruction or data of the system which is developed to the RAM2 on the basis of the contents of the RAM8 is patched and corrected. The ROM6 storing the system program including a bug is kept as it is. Thus an easy correction is ensured for the bug.