[5882] in linux-scsi channel archive
Re: WG: AW: cdrecord problems on recent Linux versions
daemon@ATHENA.MIT.EDU (Richard Gooch)
Thu Feb 11 15:56:13 1999
Date: Fri, 12 Feb 1999 07:50:56 +1100
From: Richard Gooch <rgooch@atnf.csiro.au>
To: Joerg Schilling <schilling@fokus.gmd.de>
Cc: Dominik.Stadler@btk.de, bsc@fleggaard.dk,
cdwrite@lists.debian.org, dgilbert@interlog.com,
heiko_eissfeldt@z.detesystem.de, linux-scsi@vger.rutgers.edu,
michaels@stochastik.rwth-aachen.de, xiphmont@mit.edu
In-Reply-To: <199902112038.VAA18095@fokus.gmd.de>
Joerg Schilling writes:
> >From rgooch@vindaloo.atnf.CSIRO.AU Thu Feb 11 21:29:33 1999
>
> >> >Have you heard about devfs? It allows device drivers to register
> >> >device entries which will automagically appear in /dev. It supports
> >> >the old-style names "/dev/sg0" as well as the new-style names
> >> >"/dev/sg/c0b0t0u0" (controller, bus, target, unit).
> >>
> >> >It's not just for SCSI: it's for *all* devices. It's been around for a
> >> >year now.
> >>
> >> Interesting, this is a SYSVr4 idea (around since 1987).
>
> >Perhaps. I note that the Solaris 2 implementation is in part or in
> >full a user space solution (when you do boot -r from the PROM). Their
> >scheme doesn't appear particularly robust, since old (invalid) device
> >entries are sometimes left around.
>
> This is not right, it is very robust.
>
> /dev/rdsk/c0t1d0s2 is only a symlink to the real device nodes
> which are located in /devices
>
> e.g.
>
> /dev/rdsk/c0t1d0s2 -> ../../devices/sbus@1,f8000000/esp@0,800000/sd@1,0:c,raw
>
> the /devices entries are in the real root partition but are created
> directly by the driver each time when a driver reconfiguration is done.
>
> The symlinks are created by user level programs.
> If you follow the manual and do a boot -r, these user level programs
> are called correctly and will remove unneeded entries.
>
> Howerver, it is possible to add hardware to a running system.
> Then you need to call:
>
> drvconfig tells the kernel to reconfigure the drivers
> devlinks general symlinks program
> disks symlink program for disks
> tapes symlink program for tapes
> ports symlink program for serial lines
> audlinks symlink program for audio devices
> ucblinks creates BSD compat dev entries
>
> If you don't call all programs corectly, it's your fault.
In the case I noticed recently, I think it was done correctly. Someone
upgraded the FORE ATM drivers on a system (the new drivers use
different /dev entries), booted with -r and the old device entries in
/dev were still around. This caused much confusion.
It may be a bug due to FORE not doing something right (like adding to
one of those scripts), but either way, it points to a bug/design flaw
in Solaris. Problems like this should not happen. Linux devfs doesn't
suffer from this problem.
Regards,
Richard....
-
To unsubscribe from this list: send the line "unsubscribe linux-scsi" in
the body of a message to majordomo@vger.rutgers.edu
