Re: /dev/null, NFS, sparc
Hello,
I asked about this on a local mailing list, but got no
answers; I would be interested if anyone can help me here...
> This has got me rather puzzled, I am trying to copy the
> /dev/null device on to a NFS server (the same thing
> works on a local drive).
>
> The client is Linux/sparc 2.2.x, the server is Linux/i386
> (kernel-server) 2.4.19. I don't care what the devices map to on the
> server side, only the client is important (this is a hack I am using to
> extend the amount of disk space available on the sparc).
>
> So far:
>
> donald:/usr/local/chroot/unstable/dev# rm null2
> donald:/usr/local/chroot/unstable/dev# cp -a /dev/null null2
> donald:/usr/local/chroot/unstable/dev# ls -l /dev/null null2
> crw-rw-rw- 1 root root 1, 3 May 16 2002 /dev/null
> crw-rw-rw- 1 root root 1, 1 May 16 2002 null2
>
> Also:
> donald:/usr/local/chroot/unstable/dev# mknod null2 c 1 3
> donald:/usr/local/chroot/unstable/dev# ls -l null2
> crw-r--r-- 1 root root 1, 1 Jan 12 15:49 null2
>
> strace shows:
> mknod("null2", S_IFCHR|0666, makedev(1, 3)) = 0
>
> The properties of null2 are rather different to what I want,
> in fact I think that it is /dev/mem:
>
> crw-r----- 1 root kmem 1, 1 May 16 2002 mem
>
>
> donald:/usr/local/chroot/unstable/dev# cat null2 | hexdump
> 0000000 0000 0000 0000 0000 0000 0000 0000 0000
> *
> 0003fe0 0103 0107 0000 01d8 0000 0000 0000 0000
> 0003ff0 0000 0000 0000 4000 5349 4c4f 302e 3939
> 0004000 1080 240b 0100 0000 0100 0000 0100 0000
> 0004010 a148 0000 a750 0000 1080 3354 ae10 2001
> 0004020 a148 0000 1080 322f a750 0000 0100 0000
> 0004030 a148 0000 1080 3244 a750 0000 0100 0000
> 0004040 a148 0000 1080 3269 a750 0000 0100 0000
> 0004050 a148 0000 a750 0000 1080 35d8 808c 2040
> 0004060 a148 0000 a750 0000 1080 369e 808c 2040
> [...]
>
> So is it possible to store dev major=1,minor=3 on a NFS mount, or is
> there some good reason why this isn't working?
>
> In fact if I look at any device I copied, the major and minor
> numbers always are the same.
>
> Maybe I just need some setting/option to allow devices to work?
>
> (no, I can't use devfs, this kernel is too old; I am not sure I trust
> this antique sparc computer on a newer 2.4.x kernel... Similarly,
> I cannot use mount --bind).
>
> Interestingly, the devices are all stored correctly on the server.
If there is anything else I can provide, please let me know.
My guess is that 2.2.x NFS is broken between Sparc and i386 on this old
kernel version, and that there may not be an easy solution.
--
Brian May <bam@snoopy.apana.org.au>
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