[==LFS精华系列==]实现 devfs

home_king

这里推荐两则关于devfs的资料：
http://www.atnf.csiro.au/people/rgooch/linux/docs/devfs.html
devfs的官方FAQ，尤其是Operational issues (essential reading) 部分有简洁扼要的说明。

另外，linuxfromscratch的邮件存档中也有很好的补充。
http://archives.linuxfromscratch ... 3-April/001612.html
例如，对于fstab的问题，文中提及

1. 
   
2. When you create the /etc/fstab file, make sure to use the new device names.
   
3.   +Do not use the old device names, which are only present if you run devfsd in
   
4.   +compatibility mode. These symlinks may not always be present. You can create the
   
5.   +device names as presented by the kernel, which look like
   
6.   +/dev/ide/host0/bus0/target0/lun0/part5. You can also use the symlinks which are
   
7.   +automatically generated by the kernel which look like /dev/discs/disc0/part5.
   
8.   +Note that these symlinks are always present if you use devfs without the devfs
   
9.   +daemon, so you can safely apply them in your configuration files.
   
10. 
    

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lucida

devfs可以进垃圾堆了。呵呵

home_king

最初由 penny 发表
devfs可以进垃圾堆了。呵呵

http://kerneltrap.org/node/view/1893

There are two mails below.

1. 
   
2. rom: Andrew Morton [email blocked]
   
3. Subject: Re: DevFS vs. udev
   
4. Date: Tue, 23 Dec 2003 18:38:20 -0800
   
5. 
   
6. Ian Kent [email blocked] wrote:
   
7. >
   
8. > However, if Andrew wants it gone from the kernel there is no point.
   
9. 
   
10. I do not.  devfs shall remain in 2.6 and shall continue to be supported.
    
11. 
    
12. Richard has disappeared but Andrey Borzenkov understands devfs well and
    
13. performed valuable work on it during 2.5 development.
    
14. 
    
15. 
    
16. Nor would I recommend that devfs be removed early from 2.7.x.  We should
    
17. wait until the proposed udev/sysfs solutions have matured in 2.6 and have
    
18. proven themselves in the field.  Only then will we be in a position to
    
19. confirm that devfs can be removed without causing some people unacceptable
    
20. levels of grief.    There is no rush.
    
21. 
    
22. 
    
23. And yes, there are architectural/cleanliness issues with devfs.  In 2.5
    
24. Adam Richter totally reinventing devfs's internals, basing it around the
    
25. ramfs infrastructure.  If we elect to retain devfs in 2.8 then that effort
    
26. should be resurrected.
    
27. 
    
28. 
    
29. Now would be a good time for someone to feed the whole thing through indent
    
30. though.
    

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1. 
   
2. From: Greg KH [email blocked]
   
3. Subject: Re: DEVFS is very good compared to UDEV
   
4. Date: Tue, 23 Dec 2003 15:14:57 -0800
   
5. 
   
6. On Tue, Dec 23, 2003 at 03:00:43PM -0800, Hua Zhong wrote:
   
7. > > So I cannot comment over _why_ defvs is unmaintained, but that is not
   
8. > > the point: either way, it stands that devfs is unmaintained.  
   
9. > > That is a problem in and of itself.
   
10. >
    
11. > It's just my impression that around that time core developers had
    
12. > decided to replace devfs with a new model. If I were in ths same shoes,
    
13. > I would probably also stop maintaining it. Then 2 years later when
    
14. > somebody asks, the reason to replace my code shouldn't be
    
15. > "unmaintained". Just the technical reasons should be enough. :-)
    
16. 
    
17. Back in June of 2001, Pat Mochel and I talked with Richard about this
    
18. whole driver model, sysfs, and udev design at the 2001 kernel summit,
    
19. after presenting it to all of the other kernel developers.  He had some
    
20. objections, but was very aware of what we wanted to do.
    
21. 
    
22. It's not like udev and this whole sysfs / driver model implementation
    
23. snuck into the kernel late at night when no one else was looking, and
    
24. pounced on all of the poor, unsuspecting devfs users, eating them for a
    
25. early morning snack.
    
26. 
    
27. 
    
28. greg k-h
    
29. 
    

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tram

kernel support没用啊，好多设备不support.

home_king

最初由 tram 发表
kernel support没用啊，好多设备不support.

tram老大和我们谈谈您的udev使用经验或心得啊。

tram

我也没有用udev啊，呵呵，我觉得这些新技术还是要成熟了再用比较好。比如devfs吧，我就一直觉得没有优越到哪里，/dev下面节点是少了，不过这无关紧要啊，多几个怕什么。如果要少，干脆按照硬件一个节点一个节点自己做好了。