Date: Sun, 07 Nov 1999 11:57:26 -0800 From: Mike Smith <mike@smith.net.au> To: Juergen Lock <nox@jelal.kn-bremen.de> Cc: Mike Smith <mike@smith.net.au>, zzhang@cs.binghamton.edu, freebsd-stable@FreeBSD.ORG Subject: Re: easyboot far into disk Message-ID: <199911071957.LAA13619@dingo.cdrom.com> In-Reply-To: Your message of "Sun, 07 Nov 1999 03:54:54 %2B0100." <19991107035454.B59629@saturn.kn-bremen.de>
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> > Rootdev ought to work, actually. But if you get it wrong, the loader > > will fall back to using currdev. > > Hmm then thats strange. I first tried rootdev, which didn't work, and > then later currdev, which did work, and i believe i used the same value > both times! Or was rootdev fixed only recently, the boot floppies i > had lying around and tested this on weren't the latest... I thought rootdev was fixed a long time back. If it's not, please tell me and I'll fix it again. 8) > > > Btw i remember reading in a commitlog that the concept of a `current > > > device' in loader is about to go, so maybe now this no longer works in > > > -current... > > > > The model I'm currently looking at tries to hide the way the loader > > thinks about devices as much as possible simply because it's too > > confusing. > > Well its just the BIOS' way to think about devices, isn't it? Not really; it's a confusing mix of sort-of the way the BIOS thinks about devices, and sort-of the way that we think about them. > > In -current the "best" way to tell your loaded kernel where > > to find its root filesystem is with the vfs.root.mountfrom tunable. > > But since the kernel isn't using the BIOS to mount its root that > of course still makes much more sense. (no need to fiddle with > root_disk_unit if the disk is on the second IDE channel and there > aren't two more on the first, or if there are both IDE and SCSI > disks...) That's exactly the point. The crucial problem has always been working out how to translate the BIOS unit number into a device name (or major/ minor). So we don't bother anymore (except for fall-back emergency cases). > > > (Maybe this should be added to the FAQ as a method of last resort when > > > the BIOS boot code can't see above cyl 1024?) > > > > From what I've been hearing from people lately, in most cases it's 8GB > > that's the new sound barrier, > > Yea, probably true with later boards. (anyone know if there's a > real technical reason for that, or just again short-sightedness of > the BIOS writers? I mean first 32M if i remember right, then 512M, > then 2G, now 8G... shouldn't everyone know by now that disks are > getting bigger all the time?) It's a limitation of the c/h/s interface and the practical translations available. Over 8GB we finally have to use LBA mode; the problem there is that there's still too much legacy hardware out there that will break if we default to it. > > but yes, a FAQ entry is probably worth > > writing. Go to it! > > Thats what i get for saying such things... :) Well OK, once i know > why `rootdev' didn't work i should have a try. Thanks! -- \\ Give a man a fish, and you feed him for a day. \\ Mike Smith \\ Tell him he should learn how to fish himself, \\ msmith@freebsd.org \\ and he'll hate you for a lifetime. \\ msmith@cdrom.com To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-stable" in the body of the message
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