question about building a custom kernel

[Tim Judd]

On 12/19/09, Jamie Griffin <jg at koderize.com> wrote:
> Hi
>
> I have been reading the handbook to learn about building a custom
> kernel, but just wanted to ask something about gathering information
> about my hardware before I give it a go.
>
> The handbook suggests the command:
>
> # pciconf -lv
>
> ...which I like because it provides a clear list of components I can find
> out about before I try to build the new kernel.
>
> On my system, this command does print out information for quite a few
> components, I just wondered if this information is all I need to work
> from or is it not an accurate or detailed enough representation of the
> hardware I have in my computer. I'd really appreciate any advice on how
> others go about this.
>
>         Jamie
>

Jamie,

pciconf will list pci devices only (and their derivatives, like PCI-X
and PCI-e).  ISA devices (if any) are done differently, and also usb
devices (usbdevs).  Building a custom kernel most of the time involves
the following decisions:
  embedding a firewall, so you cannot disable a firewall by unloading a module.
  Extending options, filesystem quotas for example.  The modular
kernel can add devices by modules, but can't really add options.
  Embedded solutions, like a single-purpose unit that is an all-in-one
solution.  The soekris and PC Engines firewall products come to mind.

99% of my time, I leave GENERIC (makes updating it easier with
freebsd-update) alone and load the kernel modules I need.

the amount of ram used with a GENERIC kernel and a "stripped" kernel
to your hardware may save 2MB of disk, and 1MB of RAM.  Not very worth
it for the computers today where you have TB's of disk, and GB's of
ram.


Can I ask for more details from you why you're interested in building
a custom kernel?

--TJ