Re: The advantage of modules?

Ookhoi (ookhoi@dds.nl)
Mon, 8 Jan 2001 19:26:01 +0100


Hi Michael,

> On Fri, Jan 05, 2001 at 10:50:20PM -0600, Evan Thompson wrote:
> > I'd like to know (I know, I'm being slightly off topic, while still
> > staying on topic, so I'm on topic...er...yes) if there is any
> > advantage, be it memory-wise or architectuarally wise, to use
> > modules?
> >
> > I already know the obvious points of if you are creating a distro
> > that it is usually good to make a very modular kernel for those
> > wishing not to recompile their kernel, but I was wondering if there
> > were any other advantages to using modules vs. making a monolithic
> > kernel for a kernel to be used only on one machine (with no other
> > hardware support at all)?
>
> A couple of thoughts:
>
> 1) A full kernel with everything compiled in might not fit on boot
> media such as floppies, while modules allows you to not load stuff
> that isn't needed to until after the main booting is accomplished.
>
> 2) There are several devices that have multiple drivers (such as
> tulip, and old_tulip for example). Which particular driver works
> depends on your exact particular hardware. If both of these
> drivers are linked into the kernel, whatever the kernel chooses to
> initialize first will talk to the device.
>
> 3) Having drivers as modules means that you can remove them and
> reload them. When I was working in an office, I had one scsi
> controller that was a different brand (Adaptec) than the main scsi
> controller (TekRam), and I hung a disk in a removable chasis on the
> scsi chain in addition to a tape driver and cd-rom. When I was
> about to go home, I would copy all of the data to the disk, unmount
> it, and then unload the scsi device driver. I would take the disk
> out, and reload the scsi device driver to get the tape/cd-rom. I
> would then take the disk to my home computer. I would reverse the
> process when I came in the morning.

You don't need modules for this to work.

Ookhoi
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