Date: Thu, 9 May 1996 11:23:05 -0700 (PDT) From: "JULIAN Elischer" <julian@ref.tfs.com> To: jgreco@brasil.moneng.mei.com (Joe Greco) Cc: bde@zeta.org.au, asami@cs.berkeley.edu, current@FreeBSD.ORG, nisha@cs.berkeley.edu Subject: Re: more than 32 scsi disks on a single machine ? Message-ID: <199605091823.LAA25044@ref.tfs.com> In-Reply-To: <199605091422.JAA00522@brasil.moneng.mei.com> from "Joe Greco" at May 9, 96 09:22:11 am
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> > > > >Can we connect more than 32 disks on a single machine? I tried > > > > No. > [...] > > >#define makedev(x,y) ((dev_t)(((x) << 8) | (y))) /* create dev_t */ > > > > >So it seems like we're limited to 32 disks. > > > > This limits us to 16777216 disks, or only 8388606 disks if we avoid using > > the high bit to avoid sign extension bugs. The limit is in dkunit() in > > <sys/disklabel.h> > > [...] > > There are lots of things to change. The encoding would have to be really > > ugly to preserve compatibility with existing device nodes. > > What if we don't give a damn about existing device nodes? :-) "Take the > plunge". [...] > > > I understand how this device node scheme came to be. I just happen to > think that however and whenever possible, we should work to remove such > constraints. :-) > Peter Wemm and I have designed (and I have SOME code for) a complete revamp of the disk system.. it is a total and complete rewrite, and will use a different (single) major-number/entrypoint for all disk type devices. it will require devfs to be really useful, though it can be hacked to work without it with preassigned numbers.
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