SUMMARY: A Device Question

From: \ <thursday_at_allidaho.com>
Date: Fri, 02 Jan 1914 01:04:40 -0700

Jon Norstog wrote:
>
> Summary of A Device Question
>
> Thank you all for the quick response to a basic question. There certainly
> have been changes to
> Digital Unix AKA OSF1. I am still working off the O'Reilly book, and this
> has been most helpful.
> My thought is this is the sort of basic issue that should be covered in a
> user's handbook.
>
> My basic question was this:
>
> "what is the purpose of the separate /dev and
> > > /devices directories
> > > ... and more importantly, if you are
> > > gonna try and mount a file system, which of the 4
> > > (including both block & raw devices) should you mount?
>
> "Michael A. Crowley" wrote:
> >
> > TU5.x has a fairly new way of dealing with devices that allows
> > you to live-install or remove scsi devices. Once you are used
> > to it, it is quite a good thing. It also deals with clusters
> > so there are some odd symlinks and some special symlink syntax
> > which you can see by doing listings of /dev and /tmp.
> >
> > The proper devices are similar to the old days:
> > /dev/disk/dsk8c for example
> > /dev/ntape/tape0 The norewind tape
> >
> > Get familiar with 'hwmgr' and, less so, 'dsfmgr'.
> > To start with hwmgr:
> > hwmgr sho scsi
> > hwmgr view dev
> > -mike
>
> Dr. Blinn's take on the issue is interesting
>
> > In V5.x, there is a lot of infrastructure to support TruCluster systems
> > even on stand-alone machines. /dev is now a symlink to /devices, if it
> > is a directory on your system, something is messed up. /disk is the
> > block device names used for mounts, /rdisk is the raw disk names, this
> > is something that's different between a BSD UNIX and a SysV UNIX.
>
> ... I don't have the whole panoply of CDE functions yet, so I went into the
> directories from a console window.
> /dev sure looked like a directory to me. It was just FULL of stuff.
>
> Octave Orgeron wrote:
> >
> > Hi,
> >
> > In 5.1, you'll start to see a more System V like
> > device tree. And the devices are named more logically,
> > that is why the hard drives are now named disk0c. When
> > you want to mount something, use this:
> >
> > /dev/disk/<device>
> >
> > -Octave
> >
>
> > John Losey and Paul LaMadeleine wrote similarly, combined below:
> >
> > Hello,
> >
> > From what I've seen on the systems I've upgraded to 5.x, you are
> > correct about /dev/rdisk being the raw and /dev/disk being the blocked
> > device files. My understanding is that /dev/rdisk/dsk0a was similar
> > to /dev/rrz0a and /dev/disk/dsk0a is similar to /dev/rz0a; except that
> > under the 5.x family, the old formula for determining the disk name
> > based on SCSI ID & Target no longer exists. So dsk0 could as easily
> > be on the 6th SCSI bus as on the first.
> >
> > Also, as to which should you use: /dev or /devices, on my 5.x
> > systems, /dev is symbolically linked to /cluster/members/{memb}/dev
> > and /devices is its own directory. However, if you check the inodes
> > of /dev/disk/dsk0a and /devices/disk/dsk0a with an `ls -i
> > /dev/disk/dsk0a /devices/disk/dsk0a` you'll probably notice that they
> > match (at least that's what I'm seeing here).
> >
> >
> > I personally use the /dev/disk, /dev/tape, /dev/ntape when I'm doing stuff
> > with devices. I'll use the /dev/rdisk when I need the raw devices (such
> as
> > oracle raw devices).
> >
> > I'm not sure why they made it so convolted. I've noticed it's the same
> way
> > if you're in a cluster or not.
>
> Kenneth Atchinson wrote:
>
> > Dr. John,
> >
> > Try
> > /dev/disk/dskNs
> >
> > N=scsi id
> > s=partition
> >
> > Do a hwmgr -view devices to see your disks. Here is a sample
> >
> > # hwmgr -view devices
> > HWID: Device Name Mfg Model Location
> > -------------------------------------------------------------------------
> > 3: scp (unknown) (unknown)
> > 4: /dev/kevm
> > 24: /dev/disk/floppy0c 3.5in floppy fdi0-unit-0
> > 37: /dev/disk/dsk0c SEAGATE ST19171N bus-0-targ-0-lun-0
> > 38: /dev/disk/cdrom0c DEC RRD45 (C) DEC bus-0-targ-4-lun-0
> > 39: /dev/disk/dsk1c DEC RZ1DB-CS (C) DEC bus-0-targ-1-lun-0
> > 40: /dev/disk/dsk2c COMPAQ BB00911CA0 bus-0-targ-2-lun-0
> > 41: /dev/disk/dsk3c DEC RZ2DA-LA (C) DEC bus-0-targ-3-lun-0
> > 42: /dev/disk/dsk4c DEC RZ1DF-AB (C) DEC bus-0-targ-5-lun-0
> > 43: /dev/disk/dsk5c DEC RZ1DB-CA (C) DEC bus-0-targ-6-lun-0
> >
> > Good luck.
> >
>
> Once again, Thank You one and all
>
> JN
>
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Received on Tue Feb 12 2002 - 01:30:41 NZDT