For instance, the MPLayer, Totem, GIMP, Office suits... can go all day long :).
It's actually those hardware level software that help us to get advanced information about our PC and its hardware (such as the installed RAM, HDD manufacture data, temperatures, etc). The cool thing about theses two "kinds" is that, it's pretty hard coding an app that runs at the hardware level, but writing a simple app at user level is not that hard (not always be true, any developers out there, no disrespect intended :) ).
So basically, you can create a GUI using Qt or GTK+, etc and "bind" it to a hardware level utility thus giving the user the ability to interact with that hardware level app with ease. Sorry to drag you along this long, but I kinda felt like writing a little about these things ;).
Anyway, the GNU/Linux Kernel (you must have heard of it) is the core-hardware level framework which is the heart of GNU/Linux (other than the most important ,"philosophy") and using an already built-in tools, if you hardware have physical temperature monitors, fan speed sensors, etc then all you gotta do is to find a GUI that's written to interact with the proper hardware level app (GNU/Linux Kernel in this case) which lets you see "what's happening" with ease.
In that sense, that's what Psensor is all about.
|It's Cool, right?? :)...|
It's basically a GUI written to interact with an another app that's associated with Kernel called im-sensors. So, what Psensor does is, it "calls" for the already existing hardware level app, im-sensors and reads the information it gives and then displays those information graphically so the user can see them.
Now, I know, again, I did make the developer of Psensor look a bit cheap... again sorry about that dude/dudee but I'm pretty sure it must have taken a lot of effort from their perspective. Well done! :).
If you use Ubuntu 11.04 Natty Narwhal, and if you GNU/Linux Laptop or PC supports thermal and other sensors then we can use the Psensor to display "live" details such as...
*. Temperature levels of HDD, Motherboard, CPU, GPU, etc.
*. Fan Speeds reported/supported by the lm-sensors.
*. For the above GPU, at the moment only supports Nvidia (hope it'll expand in the future). And apart from the lm-sensors, this cool utility do use nvctrl and hddtemp as well.
You can customize the Psensor GUI to desired colors as well. In Ubuntu you can install it by giving the below command in your Terminal (where else :P).
sudo apt-add-repository ppa:jfi/ppa
sudo apt-get update
sudo apt-get install psensor