Date: Wed, 19 Apr 1995 00:52:59 -0700 (PDT) From: "Rodney W. Grimes" <rgrimes@gndrsh.aac.dev.com> To: julian@ref.tfs.com (Julian Elischer) Cc: hackers@FreeBSD.org Subject: Re: [DEVFS] your opinions sought! Message-ID: <199504190752.AAA01451@gndrsh.aac.dev.com> In-Reply-To: <199504190733.AAA07567@ref.tfs.com> from "Julian Elischer" at Apr 19, 95 00:33:08 am
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> > > > > [Should this really be on 3 lists??? ] > well I wante dthe widest group :^| Okay, but one of them bounced :-( > > I think you are confused about a few things, or at least from looking > > at this it leaves me confused:-(. > > I basically want to know how people think devices (e.g. disks) > should be represented.... > how would YOU do it if you had the ideal oportunity.. > I may not be able to do everything people want but I'd like to KNOW > what they think would be best.. I take it that you mean flat vs hierarchial. How about both :-) :: mount -t devfs -o flat /dev mount -t devfs -o hier /dev I personally have always prefered the flat scheme of /dev (with possible exceptions for /dev/fd/*). This is a religious issue, I have spoken my religion. > > what I want is people's ideas on WHAT shouldbe there.. > The naming is not implimented yet because it would be the > responsibility of the SLICE code to do the naming.. the DEVFS doesn't care.. > it just shows what it's told to show by the device driver (or the slice > code in this case). Oh, in that case my -o flat/hier would intrude all over the place, oh well, guess that is out :-(. > > > > And who creates these symlinks/hardlinks? And why do we need them? > because some people want a constant way of > addressing scsi1,target2,lun0, partition b, that won't go away > or change if some OTHER device fails to probe.. This won't work if you use bus0, bus1, what happens if I pull the controller for bus 0 out of the machine. I think this is best left to the kernel config process. Even replacing bus0 with say ahc0 might not work if I had both ahc0 and ahc1 and pulled out ahc0 :-(. > a device can easily have two names, one of which is invariant.... They are always variant via config, though it is now possible at least to nail them down if you are carefull. > > How much memory does all this devfs data structure take up? > > basically, in this version, each node takes.. > > the size of the name in ascii.. > + 36 bytes > + 80 bytes > + N x 32 bytes where N is nearly always 1 > let's say 160 bytes > that seems a lot, but consider.. Sounds good, even worst caseing it find /dev | wc yields 512 devices, so that is only 81K bytes, I can easily live with that, and since this is way way overkill we are safe. -- Rod Grimes rgrimes@gndrsh.aac.dev.com Accurate Automation Company Custom computers for FreeBSD
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