efivars

Bjørn Mork bjorn at mork.no
Thu Sep 23 03:13:02 EDT 2021


Ruben Safir <ruben at mrbrklyn.com> writes:

> OS's shouldn't need anything from a boot loader.

Why do you need a bootloader then?

I'd suggest playing with embedded devices for a while. Their boot chain
is usually much simpler than on PC hardware. There you can really get a
feeling of how easy and decoupled stuff could have been. Load a kernel
directly to some location in memory and just jump there.

Then try to expand a bit by reading the kernel from some specific flash
device, or even network.  Maybe trying to make the kernel do the right
thing depending on where it was booted from.  Or add a file system to
the flash.  Etc.  Maybe you even want some way to configure the
bootloader from the OS?

Add all the features you take for granted on PC hardware.

I think you will find that the OS has to be aware of some of the stuff
the bootloader does.  And that many of the features depend on the OS
communicating with the bootloader somehow.  Both ways.



Bjørn



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