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Dear T13 Reflector Members: Devices are being equipped with sensors and software to detect external conditions that may be causing device problems such as high or low temperatures or excess vibration. These new sensors will be used only if there is a standard way to report a correctable condition. It would seem to make sense to add the ability to report temporary conditions to the SMART Return Status command. Unfortunately the design of the SMART Return Status command does not lend itself to extension. If there is no error a specific two byte code is returned in the LBA Mid and LBA High registers. If failure is predicted a different two byte code is returned. The other registers are marked na, not reserved. Adding a new return code has the potential of confusing existing SMART software, which is expecting only the two codes defined today. Using the other registers is probably not a good idea either as they are NA, not reserved, so there is no guarantee of their value in existing drives. My conclusion is that we need a new SMART Return Status Extended command that has a bit for Failure Predicted and one (or more) for Environmental Condition Notification. Existing SMART software would continue to use the current SMART Return Status command but new software, which has to poll anyway, could check for both failure prediction and an environmental condition with the same poll using the new extended command. The next question is how to report what environmental condition is out of operational range. The data could be sent back with SMART Return Status Extended, but the data would be limited to what we could put in registers. It could be returned as a group of SMART Attributes but I think that it would be better to do it as a new log page in Read Log Extended. Today I have heard of only three conditions that need to be reported, hot, cold and vibration so the problem indication can go in any of these methods. As usual, we need an Identify data bit to indicate that SMART Return Status Extended is supported. I see no reason to enable or disable the environmental reporting. I am working on a proposal document that I hope to have for next week's meeting. Please let me know what you think about how devices should report environmental conditions. Best Regards, Dan Colegrove [EMAIL PROTECTED] Senior Technical Staff Member Storage Technology Division IBM Corporation 702-614-6119 702-614-7955 fax
