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Comment by beervirus | Hacker News Reader

Why does any of this need OS support? You should be able to configure fan speed via a BIOS menu as you have been since the late 1900s.

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Scenarios that need OS support:

Your BIOS doesn't support fan speed at all.

Your BIOS doesn't doesn't support temperature-controlled fan curves, or doesn't let you customise the fan curve.

You want to use a different temperature sensor, or multiple, to control different fans, pumps, etc.

You want to schedule different fan profiles based on time of day or some other event.

Because motherboards may not have enough headers for the number of fans people want to run. And people want to be able to control things via a GUI on their OS and not have to reboot in to some ancient and buggy firmware config page.

It's not hard to see how a usb fan controller is desirable even if not strictly required.

My supermicro board fan controller is terrible (home server, so server board with silent fans). It keeps cycling up and down, which is annoying. I ended up adding a manual fan controller with a touch screen on the front of the server for all the non-CPU fans which aren’t too load specific (and I monitor the drives temperature programatically).

Apparently it’s a common problem. People write custom fan control scripts for supermicro motherboards which you can upload to the BIOS. But I didn’t want to have to learn another thing.

I think that you just have to read up about IPMI and find out some undocumented values for your board that you can find on some forum. I'm not impressed about how Supermicro handles fans, but I guess that this doesn't matter in a server room where there are no limits on how much noise the server produces.

Can't use the BIOS when I have to preserve my precious uptime. Do people still talk about uptime?

You make it sound like there isn't a real downside to closing all your programs and rebooting.

It also means you can never adjust the fans while things are hot to calibrate them.

I was being sincere! I absolutely hate rebooting, even laptops. These was a time when Linux was better about downtime-less updates too.

Oh, okay. I was thrown off because the annoyances of rebooting aren't really about uptime, per se.

Not if you run out of fan headers and need an expander.

Agreed, but I'd say USB headers are in shorter supply. And yeah, I know the 'splitters' are out there, but where the hell am I to mount that? Especially if you need more than one, since for some reason they only give you two headers for the price of one.

USB3 headers are in short supply, but this looks like it uses a USB2 header, no?

> Especially if you need more than one, since for some reason they only give you two headers for the price of one.

USB 2.0 headers have 8 working pins and 2 ports. It's physically impossible to split them into more than two. Splitters aren't hubs.

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