Dual Dump Location for Internal Error Trap
Original Publication Date: 2001-Feb-01
Included in the Prior Art Database: 2003-Jun-19
Disclosed is a method to preserve internal state certainly on a detection of exception process. Some devices whose processing system are complicate, like HDD, employ a technique to preserve the internal state on a detection of the exception process by itself. This is to understand what happened on the instance of the exception without duplicating the exception. This method is famous for "Black Box" on aircraft. There are two detection types of exception process for HDD. One is that it is detected by the HDD itself, exactly microcode in the HDD. And another is that it is detected by host controller. If microcode detects the exception process and is able to continue the further process, microcode preserved the internal state by itself. But if the exception occurs while microcode does not recognize or it is impossible to continue the further process on the exception, POR(Power On Reset) is proceeded by HDD. The host controller can recognize this HDD behavior as an illegal process then may issue a command to preserved the internal state against the HDD. The problem is in case that microcode has already preserve the internal state but the host controller also issues a command to preserve the state after that. The internal state on the instance of the exception will be over-written by the state after that. This disclosure can prevent such data lost and keep the proper internal state certainly.