/s Gather around children. Let me tell you a story from long long time ago. Two one eyed giants, Intel and Microsoft got together and decided that they should

/s Gather around children. Let me tell you a story from long long time ago. Two one eyed giants, Intel and Microsoft got together and decided that they should be in control of your machine, not the other half giants, like AMI, Award,Phoenix, DTK, and even a full giant but nobody cared about her, IBM. So they convinced everyone there was no space on the BIOS any more, and they had to shift much of the code outside onto a boot device, usually an HDD. 'Think about all the speed and ability to update quickly' they said to the peasants, and the local magistrates in the form of media gobbled it up, and continue to spread this news. There were some peasants that freaked out, pointed out the problem, but quickly were shouted down and jeered at by the crowd. 'We want faster! Stop spreading misinformation.' And, the two giant indeed forced the development of EFI then UEFI. There is nothing Unified about it. But, guess what? That was not good enough either, because some peasants figured it out how to manipulate the UEFI, and the two giant didn't like that. So they went back to the half giants and discussed what to do. And, lo they came up with an brand new idea! What if we put all this information into a chip, and make it hard to read! We will call it, BIOS! For good measure, for peasants that want more power, we will even throw in another one, and we will call it Baseboard Management Controller, but we will let you call that all kinds of different names! To make it even more entertaining, in larger cities where peasants are promoted to the rank of "enterprise", some host board adapters will also run OSes themselves for the fun of it. And this is how we got to today. When your computer runs, the BIOS with a full OS can be running, next to it, the BMC with a full OS could be running, on top of the BIOS you can have UEFI running, the HBA OSes running, and finally your very safe and secure OS running. /story I have taken artistic liberty (like UEFI most often runs on the same CPU,while BMC & HBA run on their own, and such), but the gist is true. An enterprise class host can be running many fully functional OSes, potentially with full network stack. This is why "zero trust" network implementation is so important.