Patch Code Control for Microcode in ROS
Original Publication Date: 1986-Mar-01
Included in the Prior Art Database: 2005-Mar-08
Applying patch code to microcode in ROS (read-only storage) is controlled by checking the patch code level and the ROS level. The function of a machine is controlled by the microcode, and a part of microcode is stored in ROS and the rest is loaded into a memory from a diskette. When a defect is found in ROS, a ROS patch code is loaded from a diskette. However, if a machine level that is ROS code is changed, applying a ROS patch code to the machine of various levels uniformly will cause some trouble (Fig. 1). To avoid this trouble, a ROS patch code is tagged with the LevelID which indicates the applicable machine level, and various ROS patch codes are stored in a diskette to meet various levels of ROS.