Since heat has become much more of a concern for newer
drives, particularly high-end ones, some manufacturers have added a very good reliability
feature to their drives: thermal monitoring. IBM calls this feature the Drive
Temperature Indicator Processor or Drive-TIP. It has also been implemented
by at least one other manufacturer (Western Digital).
The idea behind this feature is very simple: a temperature sensor is mounted on the
drive, usually on the logic board, and it records the temperature of the drive
periodically over time. One or more trip points are set within the drive's
control logic, and status notifications are sent by the drive back to the system if they
are exceeded. Normally, thermal monitoring is integrated with the drive's SMART feature for reporting. A typical setup is two trip
points, one at 60°C and another at 65°C; the first trip point can be changed by the user
of the drive while the second often cannot. The controller may also keep track of the
highest temperature ever recorded by the drive, and may also take action on its own accord
if the trip point(s) are exceeded, such as slowing down the drive's activity or even
shutting it down completely. The exact implementation depends on the manufacturer.
Due to mechanical failure--for example, a case cooling fan that
malfunctions--overheating is possible even in a system properly designed to avoid such
problems under normal circumstances. This makes temperature monitoring a very useful and
important feature for systems were reliability is essential. It is more often found on
high-end SCSI units than consumer-grade drives, but it seems likely to me that in the
future it will become standard on most drives.
Next: Expanded Remapping and Spare Sectoring
