> Those drivers need to actually communicate with something though, that something is exactly what BMCs are. If the hardware physically providing communication

> Those drivers need to actually communicate with something though, that something is exactly what BMCs are. If the hardware physically providing communication with those systems isn't there, no amount of drivers will help. Additionally, many of those things have to be configured before the OS is loaded and the hardware they control is fully initialized. Not possible inside the OS. You're going to have a chicken and egg situation at boot. The SATA/SAS HBA needs some code to read the OS with, but in a sense this is just a piece of your OS that has to be installed on the HBA, in the same way as grub has to be installed in the boot partition. Once the OS is running it can load different code into the HBA or replace the code that will run on the next boot. We can argue about whether to call that sort of code a BMC or not but the more important question is if people can replace it or not, so that people can fix things the manufacturer doesn't.