What's this /run directory doing on my system and where does it come from?

[Ralf Corsepius]

On 03/30/2011 03:21 PM, Lennart Poettering wrote:
> On Wed, 30.03.11 15:08, Ralf Corsepius (rc040203 at freenet.de) wrote:
>
>>
>> On 03/30/2011 02:30 PM, Lennart Poettering wrote:
>>> On Wed, 30.03.11 18:04, Rahul Sundaram (metherid at gmail.com) wrote:
>>>
>>
>>> Also, can somebody point me to the place where the FHS would say "no
>>> other directories below / are allowed"? I can't find that. And hence
>>> this change is perfectly FHS compliant.
>>
>> It's in the preface of the root file system section:
>>
>> http://www.pathname.com/fhs/pub/fhs-2.3.html#THEROOTFILESYSTEM
>>
>> <cite>
>> Applications must never create or require special files or
>> subdirectories in the root directory. Other locations in the FHS
>> hierarchy provide more than enough flexibility for any package.
>> </cite>
>
> Well, we are not an "application", are we?

I feel you are violently not wanting to understand and prefer tearing 
things into the absurd:

a) systemd is the application this all has begin with.
b) what else but applications are creating "run" files?

Ralf