I'm trying to figure out how to properly blacklist a module (persistently), and the following is a bit confusing:
Let's take module "floppy" for example. From what I've gathered, the proper procedure is:
1. Create a .conf file under /etc/modprobe.d/
2. Update initrd image:
$ sudo vim /etc/modprobe.d/blacklist-floppy.conf
$ sudo update-initramfs -u
This procedure works great, but what exactly does step 2 do? I would think that it would recreate the initrd image with a slight change, telling it not to load the floppy module, which I guess implies that the initrd image is responsible for telling the kernel which modules to load - is this assumption correct?
Without step 2, the change does not take effect, and the floppy module is still running after a reboot even though the blacklist-floppy.conf file is present. With it, if I want to unblacklist the floppy module, all I do is remove the file blacklist-floppy.conf and reboot and it takes effect - running step 2 again does not seem to be necessary to reverse the procedure. What exactly is step 2 doing?