John Rigg <dev1@???> wrote:

> Wasn't the original reason for having an initrd that the boot loader,
> probably LILO at the time, couldn't handle a kernel image above a
> certain size?

I suspect you are thinking of the problem that it couldn't access sectors past a certain point due to limitation in the BIOS - that was the reason for a separate /boot which meant you could guarantee to have any future kernel within the range accessible to LILO.

The separate issue is having a modular kernel - which I'm in favour of BTW. If you use LVM, MD (raid), disk controllers needing a kernel module, or one of a few other things - then you can have a catch-22 situation where the kernel needs to load a module to access a filesystem, but can't until it's mounted that filesystem, which of course it can't do. Hence the idea of initramfs where everything the kernel needs to be able to access and mount the root fs (eg disk controller drivers, lvm, md) is included in a "packed up" filesystem that can be loaded into ram and then used as a temporary root until such time as the real root can be loaded.

I can see why distros would include everything and the kitchen sink - otherwise you get the amusing situation I've seem at work where the Windows installer can't see the disks until someone does the "insert device driver disk" steps to give the kernel access to it. But as pointed out, for most users, something simpler would be adequate.