Thanks for the link, Artie. Temperature Monitor seems to be a nifty (and free) app that monitors and reports several internal temperatures in addition to that of the hard disk. The vendor's web site FAQs makes the following interesting observations:

"S.M.A.R.T. is the abbreviation of Self Monitoring, Analysis, and Reporting Technology . It is an industry standard introduced in 1992 to react earlier on hard disk failures. A hard disk supporting the S.M.A.R.T. standard monitors itself with its own micro processor and allows the operating system to request readouts that indicate whether operational parameters have changed in such a way that the hard disk might become defective in the near future. In this case the hard disk can be replaced before any data is lost.

Some hard disk manufacturers allow the computer to request additional detail information, e.g. the current operating temperature of the disk. However, this feature is not an official part of the S.M.A.R.T. standards. Not every disk supporting S.M.A.R.T. is capable of providing temperature readings. Either the data is not measured at all, or the hard disk manufacturer did not publish how the data can be read out from the disk controller." I had not understood earlier that temperature parameters are not a routine part of the SMART report in all cases.

Temperature Monitor FAQs also discusses the question of what value for a given computer is WNL and the app provides the user with a table which will identify that value if Apple has specified a range. If no range is listed, Apple has not published one. There is no SMART temp normal range listed in the table. The FAQ then states, "Note that all up-to-date Macintosh models automatically shut down or enter sleep mode if one of the readings exceeds a critical limit. For this reason it is impossible that your computer can be damaged in an overtemperature condition." This is essentially what Apple tech support told me, too. In other words, the data is apparently only academic, so don't worry. But if this is the case, then how does TTP/MM know when a hard disk temp is too high and needs to reports it as a SMART failure? Perhaps MMT3 can provide some insight here.






"For every complex problem, there is a simple, easy to understand, incorrect answer."

Albert Szent-Gyorgyi