libsensors0 is a library to read temperature/voltage/fan sensors
lm-sensors "Kernel drivers to read temperature/voltage/fan sensors. This is a module for reading the temperature/voltage/fan sensors in Linux via the LM78/79 chip and possibly sensors on the SMBus (System Management Bus, usually found in P6 and P-II systems). The LM80 and a LM78-clone called W83781D are also supported." http://www.lm-sensors.nu/
ACPI, see APM chapter