Editing BIOS (section)

=== Hardware monitoring ===
{{Main|Hardware monitoring}}
A modern BIOS setup screen often features a '''PC Health Status''' or a '''Hardware Monitoring''' tab, which directly interfaces with a Hardware Monitor chip of the mainboard.<ref name=sensors-mmath>{{cite thesis
|degree= [[Master of Mathematics#Canada|MMath]]
|author= Constantine A. Murenin |date= 2010-05-21
|section = 11.1. Interfacing from the BIOS
|title= OpenBSD Hardware Sensors – Environmental Monitoring and Fan Control.
|location= [[University of Waterloo]] |publisher= UWSpace
|url = http://cnst.su/MMathCS |hdl = 10012/5234
|id = Document ID: ab71498b6b1a60ff817b29d56997a418.
}}</ref> This makes it possible to monitor CPU and [[computer case|chassis]] temperature, the voltage provided by the [[power supply unit (computer)|power supply unit]], as well as monitor and [[computer fan control|control the speed of the fans]] connected to the motherboard.

Once the system is booted, hardware monitoring and [[computer fan control]] is normally done directly by the Hardware Monitor chip itself, which can be a separate chip, interfaced through [[I²C]] or [[System Management Bus|SMBus]], or come as a part of a [[Super I/O]] solution, interfaced through [[Industry Standard Architecture]] (ISA) or [[Low Pin Count]] (LPC).<ref name=ieee07>{{Cite conference
|author= Constantine A. Murenin |date= 2007-04-17
|url = http://sensors.cnst.su/IEEE_ICNSC_2007
|section = 2. Hardware review
|title= Generalised Interfacing with Microprocessor System Hardware Monitors
|conference= Proceedings of 2007 IEEE International Conference on Networking, Sensing and Control, 15–17 April 2007.
|location= London, United Kingdom
|publisher=[[Institute of Electrical and Electronics Engineers|IEEE]]
|pages = 901–906 |doi = 10.1109/ICNSC.2007.372901 |isbn = 978-1-4244-1076-7
|id = IEEE ICNSC 2007, pp. 901—906.
}}</ref> Some operating systems, like [[NetBSD]] with [[envsys]] and [[OpenBSD]] with sysctl [[hw.sensors]], feature integrated interfacing with hardware monitors.

However, in some circumstances, the BIOS also provides the underlying information about hardware monitoring through [[Advanced Configuration and Power Interface|ACPI]], in which case, the operating system may be using ACPI to perform hardware monitoring.<ref name=aibs.4>{{cite web|url=http://mdoc.su/-/aibs.4|title=aibs – ASUSTeK AI Booster ACPI ATK0110 voltage, temperature and fan sensor|publisher=[[OpenBSD]], [[DragonFly BSD]], [[NetBSD]] and [[FreeBSD]]|date=2010}}</ref><ref>{{Cite web|title=acpi_thermal(4)|url=https://www.freebsd.org/cgi/man.cgi?query=acpi_thermal&sektion=4|access-date=2021-02-24|website=www.freebsd.org}}</ref>