bsdhwmon(8) is a program for FreeBSD for monitoring hardware sensors (fans,
temperatures, voltages, chassis intrusion, and more) on commerical-grade server
hardware. bsdhwmon(8) is developed with a very different mentality compared to
other softwares:

- Written with stability and production datacenter environments in mind
- Intended for use with server products (Intel, Supermicro, Tyan, and possibly
  others)
- Solely uses smb(4), significantly decreasing risks and CPU usage
- Based heavily on documentation provided from the server and H/W monitoring IC
  manufacturers
- Full tested on both i386 and amd64 systems, using RELENG_6, RELENG_7, 
  RELENG_8 and RELENG_9
- Written entirely in C
- Completely standalone; relies on no third-party libraries or tools (autoconf,
  etc.)
- Very simple and clean code (heavily commented, well-documented, emits no
  warnings)
- Open-source, released under the FreeBSD 2-clause BSD license

WWW: http://bsdhwmon.koitsu.org/