Why must I modprobe?

[Alexander Skwar]

David Abrahams <dave at boost-consulting.com>:

> Alexander Skwar <listen at alexander.skwar.name> writes:
> 
>> Gabriel Dragffy <dragffy at yandex.ru>:
>>
>>> I'm trying the following command:
>>> $ sudo lvcreate --size 100m --snapshot --name snap /dev/bouncyball/root
>>> 
>>> and getting the error:
>>>   snapshot: Required device-mapper target(s) not detected in your kernel
>>>   lvcreate: Create a logical volume
>>> 
>>> I have tried many other combinations including the -s and -n switches
>>> but still no joy, what am I overlooking?
>>
>> You're overlooking the message that lvcreate is telling you:
>>         
>>         Required device-mapper target(s) not detected in your kernel
>>
>> Solution: Enable the kernel to support snapshots.
>>
>>         modprobe dm-snapshots   (or something like this)
> 
> Alright, this has been bugging me for a while, and this gives me
> occasion to ask.  Why does Linux require me to do this, rather than
> simply auto-loading modules when an attempt is made to use their
> functionality?

Back in the days, something like this used to work. But I think at
about the time when 2.6 became stable, this functionality has been
dropped. Or was it because of udev? Or devfs?

Anyway. Way back then, this used to work. But nomore - or at least,
I don't know how to get it to work.

> It's a serious usability blocker: 

Yep.

Alexander Skwar
-- 
"He don't know me vewy well, DO he?"   -- Bugs Bunny