hw.sensors
{{Short description|Hardware monitoring sensors framework}}
{{lowercase}}
{{Use mdy dates|date=March 2019}}
{{Infobox software
| name = hw.sensors
| author = Constantine A. Murenin (2006),
Alexander Yurchenko (2003–2004)
| developer = The OpenBSD Project
| released = {{Start date and age|2003|04|25|df=yes}}
| programming language = C
| operating system = OpenBSD, DragonFly
| genre = system monitoring
| licence = ISC
}}
The hw.sensors framework is a kernel-level hardware sensors framework originating from OpenBSD, which uses the sysctl kernel interface as the transport layer between the kernel and the userland. {{As of|2019}}, the framework is used by over a hundred device drivers in OpenBSD to export various environmental sensors, with temperature sensors being the most common type. Consumption and monitoring of sensors is done in the userland with the help of sysctl, systat, sensorsd, OpenBSD NTP Daemon (OpenNTPD, ntpd), Simple Network Management Protocol (snmpd), ports/sysutils/symon and GKrellM.
Drivers
In OpenBSD, the framework is integrated with Dell's ESM, Intelligent Platform Management Interface (IPMI) and I2C, in addition to several popular Super I/O chips through {{URL|http://mdoc.su/o/lm.4|lm(4)}}.
A major difference compared to other solutions like lm_sensors is simplicity and a works-by-default approach in the drivers, which don't need or support any configurability; no installation or configuration actions are required by the system administrator to get the sensors going. This is coupled with a fine-tuned ad-hoc read-only scan procedure on the I2C bus, written by Theo de Raadt in a centralised way with a cache, making it possible to leave it enabled by default at all times, unlike the competing solutions.
= RAID <code>drive</code> sensors =
{{anchor|drive|SENSOR_DRIVE}}
Support for automatic monitoring of RAID drives is also provided through the sensors framework, this concept of sensors of drive type has been backported by NetBSD back into envsys in 2007.
= OpenNTPD <code>timedelta</code> sensors =
{{anchor|timedelta|SENSOR_TIMEDELTA}}
OpenNTPD uses sensors of type timedelta to synchronise time. These are provided by NMEA and other drivers.
History
The framework was originally devised in 2003 by Alexander Yurchenko, when he was porting several envsys-based drivers from NetBSD. Instead of porting NetBSD's envsys, a simpler sysctl-based mechanism was developed.
Framework use by the device drivers rose sharply with the release of OpenBSD 3.9. Then, in only 6 months, the number of individual drivers using the framework rose from 9 in OpenBSD 3.8 (released {{dts|2005|11|01|format=dmy}}) to 33 in OpenBSD 3.9 (released {{dts|2006|05|01|format=dmy}}).
{{As of|2006|12|23}}, the framework was used by 44 devices drivers. At this time, a patchset was committed converting a simple one-level addressing scheme into a more stable multi-layer addressing.
In 2007, the framework was ported to FreeBSD as part of a Google Summer of Code grant. It was adopted by DragonFly BSD later that year. The usability of the {{URL|http://mdoc.su/o/sensorsd.8|sensorsd(8)}}, the sensor monitoring daemon, was vastly improved in 2007, partly via the same GSoC grant.
{{As of|2008|11|01}}, the total number of drivers stood at 68 in OpenBSD 4.4; growing by 7 drivers in a 6-month release cycle. This rate of growth, of one new driver per month on average, has been common throughout the history of the framework since OpenBSD 3.9.
The values exported by the drivers through the framework are read-only; however, an external patch exists that implements the fan control functions in both the framework, and in one of the drivers for the most popular family of Super I/O chips. This patchset was provided for both OpenBSD and DragonFly BSD.
See also
{{Portal|Free and open-source software}}
References
{{Reflist
|refs=
|url=https://www.zdnet.com/article/openbsd-3-9-adds-sensor-framework/
|title=OpenBSD 3.9 adds sensor framework
|author=Ingrid Marson
|publisher=ZDNet
|date=2006-03-24 |access-date=2019-03-04
}}
|url=https://www.linux.com/news/interview-theo-de-raadt-openbsd
|title=Interview: Theo de Raadt of OpenBSD
|author=Manolis Tzanidakis
|publisher=Linux.com
|date=2006-03-28 |access-date=2019-03-04
}}
|url=https://wiki.freebsd.org/GSoC2007/cnst-sensors
|title=GSoC2007/cnst-sensors
|author=Constantine A. Murenin
|publisher=FreeBSD
|date=2007-10-14 |access-date=2019-03-04
}}
|url=http://kerneltrap.org/OpenBSD/BSDCan_2008_Hardware_Sensors_Framework
|title=BSDCan 2008: Hardware Sensors Framework
|author=Jeremy Andrews
|website=KernelTrap
|date=2008-06-07 |archive-url=https://web.archive.org/web/20101218045620/http://kerneltrap.org/OpenBSD/BSDCan_2008_Hardware_Sensors_Framework
|access-date=2019-03-04
|archive-date=December 18, 2010
}}
|url=http://ports.su/sysutils/gkrellm/gkrellm,-main
|title=gkrellm-server-2.3.10p1 – single process stack of system monitors for GTK+2 (server)
|work=OpenBSD ports
|date=2018-06-01 |access-date=2019-03-04
}}
|url=http://onlamp.com/lpt/a/7155
|title=Puffy's Marathon: What's New in OpenBSD 4.2
|author=Federico Biancuzzi
|publisher=O'Reilly Media
|date=2007-11-01 |archive-url=https://web.archive.org/web/20111013021755/http://onlamp.com/lpt/a/7155
|access-date=2019-03-03
|archive-date=October 13, 2011
}}
- {{cite web |title=Puffy's Marathon: What's New in OpenBSD 4.2 - ONLamp.com |url=https://undeadly.org/cgi?action=article&sid=20071102080000 |website=Undeadly}}
|url=http://broadcast.oreilly.com/2008/11/source-wars---return-of-the-pu.html
|title=Source Wars - Return of the Puffy: What's New in OpenBSD 4.4
|author=Federico Biancuzzi
|publisher=O'Reilly Media
|date=2008-11-03 |archive-url=https://web.archive.org/web/20120524040127/http://broadcast.oreilly.com/2008/11/source-wars---return-of-the-pu.html
|access-date=2019-03-03
|archive-date=May 24, 2012
}}
|author1=David Gwynne
|author2=Marco Peereboom
|date=2006-12-03
|url=https://www.openbsd.org/papers/opencon06-bio.pdf
|title=bio and sensors in OpenBSD
|conference=OpenCON 2006, 2–3 December 2006
|location=Courtyard Venice Airport, Venice/Tessera, Italy
|access-date=2019-03-04
}}
|author=Constantine A. Murenin
|date=2007
|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
|id=IEEE ICNSC 2007, pp. 901—906.
|doi=10.1109/ICNSC.2007.372901
}}
|author=Constantine A. Murenin
|editor=Marco Peereboom
|date=2006-12-30
|url=https://undeadly.org/cgi?action=article&sid=20061230235005
|title=New two-level sensor API
|website=OpenBSD Journal
|access-date=2019-03-04
}}
|author=Marc Balmer
|date=2007-03-15
|url=https://www.openbsd.org/papers/radio-clocks-asiabsdcon07.pdf
|title=Support for Radio Clocks in OpenBSD
|conference=AsiaBSDCon 2007 Proceedings, 8–11 March 2007
|location=Tokyo, Japan
|publication-date=2007-03-10
|archive-url=https://web.archive.org/web/20080827225534/https://2007.asiabsdcon.org/papers/P03-paper.pdf
|archive-date=2008-08-27
|url-status=live
|access-date=2019-03-04
}}
- {{cite web |author=Marc Balmer |date=2007-09-16 |title=Supporting Radio Clocks in OpenBSD |url=https://www.openbsd.org/papers/eurobsdcon07/mbalmer-radio_clocks.pdf |website=OpenBSD}}
|author1=Constantine A. Murenin
|author2=Raouf Boutaba
|date=2009-03-17
|url=https://www.openbsd.org/papers/asiabsdcon2009-sensors-paper.pdf
|title=OpenBSD Hardware Sensors Framework.
|conference=AsiaBSDCon 2009 Proceedings, 12–15 March 2009
|location=Tokyo University of Science, Tokyo, Japan
|publication-date=2009-03-14
|archive-url=https://web.archive.org/web/20090221000000/https://www.openbsd.org/papers/asiabsdcon2009-sensors-paper.pdf
|archive-date=February 21, 2009
|url-status=live
|access-date=2019-03-04
}} [https://2009.asiabsdcon.org/papers/abc2009-P3B-paper.pdf Alt URL]
|url=http://sensors.cnst.su/fanctl/
|author=Constantine A. Murenin
|date=2010-03-14 |access-date=2019-03-04
|title=Quiet computing with BSD: Fan control with sysctl hw.sensors and lm(4) on OpenBSD and DragonFly BSD
}}
|url=https://cvsweb.openbsd.org/cgi-bin/cvsweb/src/sys/dev/i2c/i2c_scan.c
|author=Theo de Raadt
|author-link=Theo de Raadt
|date=2015-05-29 |access-date=2019-03-04
|title=/sys/dev/i2c/i2c_scan.c
|website=Super User's BSD Cross Reference
}}
|url=https://cvsweb.openbsd.org/cgi-bin/cvsweb/src/usr.sbin/ntpd/sensors.c
|author=Henning Brauer
|date=2016-09-03 |access-date=2019-03-04
|title=ntpd/sensors.c
|website=Super User's BSD Cross Reference
}}
|url=https://cvsweb.openbsd.org/cgi-bin/cvsweb/src/sys/kern/tty_nmea.c
|author=Marc Balmer
|date=2019-01-26 |access-date=2019-03-04
|title=/sys/kern/tty_nmea.c
|website=Super User's BSD Cross Reference
}}
|type=MMath
|author=Constantine A. Murenin
|date=2010-05-21
|title=OpenBSD Hardware Sensors — Environmental Monitoring and Fan Control.
|location=University of Waterloo, Waterloo, Ontario, Canada
|publisher=UWSpace
|url=http://cnst.su/MMathCS
|hdl=10012/5234
|id=Document ID: ab71498b6b1a60ff817b29d56997a418.
}}
}}
{{Refbegin}}
{{Refend}}
External links
- {{URL|https://cvsweb.openbsd.org/cgi-bin/cvsweb/src/sys/sys/sensors.h}}
- {{URL|https://www.openbsd.org/papers/asiabsdcon2009-sensors-paper.pdf|asiabsdcon2009-sensors-paper.pdf}}
- {{URL|https://www.openbsd.org/papers/asiabsdcon2009-sensors-slides.pdf|asiabsdcon2009-sensors-slides.pdf}}
{{OpenBSD}}
{{DragonFly}}