Mkinitrd creates filesystem images which are suitable for use as
Linux initial ramdisk (initrd) images.  Such images are often used
for preloading the block device modules (such as IDE, SCSI or RAID)
which are needed to access the root filesystem.  Mkinitrd automatically
loads IDE modules, all scsi_hostadapter entries in /etc/modules.conf,
and raid modules if the system's root partition is on raid, which
makes it simple to build and use kernels using modular device drivers.

In other words, generic kernels can be built without drivers for any
IDE/SCSI/RAID adapters which load appropriate driver as a module.
Since the kernel needs to read those modules, but in this case it
isn't able to address the IDE/SCSI/RAID adapter, an initial ramdisk
is used.  The initial ramdisk is loaded by the operating system loader
(such as LILO or GRUB) and is available to the kernel as soon as the
ramdisk is loaded.  The ramdisk image loads the proper IDE/SCSI/RAID
adapter and allows the kernel to mount the root filesystem.
The mkinitrd program creates such a ramdisk using information found in
the /etc/modules.conf file.

• L.A. Kostis
• Sergey Vlasov
• Dmitry V. Levin

• mkinitrd