[Beowulf] cloning issue, hidden module dependency

David Mathog mathog at caltech.edu
Mon Dec 8 15:15:40 PST 2008

Bogdan Costescu wrote:

> Having a monolithic kernel that "just works" on a large variety of 
> hardware means answering "y" to most drivers; the kernel itself would 
> then grow as large as the "immense initrd" that you mention. 

I don't think so. It only has to work with a large variety of disks, and
at that, not necessarily at optimal speeds.  Basically it just has to
function well enough to access the OS files on disk, where the rest of
the modules are, so that those drivers can be loaded later.  The boot
kernel need not have every video, network, etc. driver in it.  

In any case, the sizes of the vmlinuz/initrd files discussed so far

Distro            Kernel     vmlinuz  initrd Kernel has IDE builtin
Mandriva 2007.1  (  1607583  357892   Y
Mandriva 2008.1  (  1787352 2214302   N
Ubuntu 8.04.1    ( 1903448 7906356   N

Sure this is apples and oranges, but to me it looks like taking the IDE
stuff (and maybe other drivers) out of the boot kernel is resulting
in larger and larger initrd files, with the size of initrd going up
faster than the size of vmlinuz, by a lot.


David Mathog
mathog at caltech.edu
Manager, Sequence Analysis Facility, Biology Division, Caltech

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