problemy z devfs

Paweł Gołaszewski blues w ds.pg.gda.pl
Pon, 16 Cze 2003, 19:48:23 CEST


On Mon, 16 Jun 2003, Jacek Konieczny wrote:
> > Różnica jest taka, że całość jest robiona w userlandii przez małego
> > demona. AFAIR to robi on normalne wpisy w /dev/ Całość jest podobno
> > _znacznie_ prostsza i łatwiejsza w utrzymaniu, a ma zalety i devfs i
> > starego /dev
> Zdaje się że devfs potencjalnie umożliwiało pozbycie się ograniczenia
> numerków major, których niedługo może zabraknąć, a także uniknięcie
> konfliktów w numeracji. A robienie zwykłych wpisów w /dev w userland
> tych zalet napewno nie ma.

Nie wiem - nie znam szczegółów rozwiązania. Wydaje mi się, że z tym też 
będzie możliwość poradzenia sobie...

<cite>
I'd like to finally announce the previously vapor-ware udev program that                                                                                       
I've talked a lot about with a lot of people over the past months.  The                                                                                        
first, very rough cut is at:                                                                                                                                           
kernel.org/pub/linux/utils/kernel/hotplug/udev-0.1.tar.gz                                                                                                                                                                                                                                                             
But what is it?  I've included an initial design document below that was                                                                                       
originally written by Dan Stekloff, and hacked up a bit by me.  But in                                                                                         
short, udev is a userspace replacement for devfs.  It will create and                                                                                          
destroy /dev entries based on the current system configuration.  It does                                                                                       
this by watching the /sbin/hotplug events on the system, and reading                                                                                           
information about these events from sysfs.                                                                                                                                                                                                                                                                                    
Right now the program is only in 1 piece, not the 3 pieces that the                                                                                            
design document talks about, but it does work with the default Linux                                                                                           
/dev naming scheme that almost everyone uses.  It can only work for                                                                                            
devices that create a dev file in sysfs, exposing their major/minor                                                                                            
number, so this is limited (currently only block and usb-serial devices                                                                                        
do this.)                                                                                                                                                                                                                                                                                                                     
If you want to test this with block devices, you will need the kobject                                                                                         
hotplug patches previously posted here for 2.5.67, which are also                                                                                              
available at:                                                                                                                                                          
kernel.org/pub/linux/kernel/people/gregkh/misc/kobject-hotplug-?-2.5.67.patch                                                                                                                                                                                                                                         
Anyway, this works for me, on my machines, and I am very interested in                                                                                         
feedback from everyone about both this concept, and the implementation                                                                                         
of this.  I've cced a lot of different lists, as they have all expressed                                                                                       
interest in this project.                                                                                                                                                                                                                                                                                                     
Yes, I know there's still a lot of work to do (serialization, symlinks,                                                                                        
hooking hotplug so that others can also use it, etc.) but it's a first                                                                                         
step :)                                                                                                                                                                                                                                                                                                                       
I'd like to thank Dan Stekloff for constantly badgering me about this                                                                                          
project and for writing lots of good design documentation, it is greatly                                                                                       
appreciated.  Also, thanks to Pat Mochel for coming up with sysfs which                                                                                        
allows this project to be able to work at all.                                                                                                                                                                                                                                                                                
thanks,
greg k-h
</cite>

> /dev/{scsi,ide}/..., /dev/cdroms/... to IMHO genialne rozwiązania, mimo
> że długie ścieżki do urządzeń są czasem niewygodne.

/dev/.../.../lun/.../../part1
Zarąbiście wygodne...

-- 
pozdr.  Paweł Gołaszewski 
---------------------------------
worth to see: http://www.againsttcpa.com/
CPU not found - software emulation...



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