Date: Thu, 16 Mar 95 13:37:09 MST From: terry@cs.weber.edu (Terry Lambert) To: wollman@halloran-eldar.lcs.mit.edu (Garrett Wollman) Cc: phk@ref.tfs.com, rgrimes@gndrsh.aac.dev.com, current@FreeBSD.org Subject: Re: newfs: sectors per cylinder (4096) disagrees with disk label (36) Message-ID: <9503162037.AA24374@cs.weber.edu> In-Reply-To: <9503161704.AA21423@halloran-eldar.lcs.mit.edu> from "Garrett Wollman" at Mar 16, 95 12:04:01 pm
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> > # of SCSI controllers > > * # of SCSI devices per bus > > * # of SCSI LUNs > > * # of partitions (regular and extended) > > * # of BSD slices per partition > > Try again: > > # of SCSI disks > * # of slices (regular and extended) + 1 > * # of BSD partitions per slice > > We do not now have, nor do we plan to start having, device nodes directly > naming SCSI addresses. Excuse me, that's not what I said, is it? Let me point out that: > # of SCSI disks == > > # of SCSI controllers > > * # of SCSI devices per bus > > * # of SCSI LUNs AND > * # of slices (regular and extended) + 1 == > > * # of partitions (regular and extended) + 1 (to grant you an unnecessary abstraction that can be worked around by adding a single ioctl) AND > * # of BSD partitions per slice == > > * # of BSD slices per partition + an irrelevent terminology change Calculations wherein you arrive at a number (n+1)/n times larger than mine for n = "# of slices (regular and extended)". Before you go off on "# of SCSI controllers" vs. "major numbers", note that I did include this option in the unquoted portion of my post. It only reduces the need to less than 32 bits but still more than the 16 bits you'd expect. The number of devices that must be addressed is the relevent issue, not how one chooses to address them (although adding (n+1)/n times the number of devices does strike me as particularly inelegant). Terry Lambert terry@cs.weber.edu --- Any opinions in this posting are my own and not those of my present or previous employers.
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