Subject: Re: Another changer, another changer problem
To: None <email@example.com>
From: Greg A. Woods <firstname.lastname@example.org>
Date: 10/01/1998 21:26:04
[ On Thu, October 1, 1998 at 18:02:04 (-0700), C Kane wrote: ]
> Subject: Re: Another changer, another changer problem
> Using a link misses the point. I want nailed-down names so device-
> renaming does not occur on bootup.
Well, you can do that in custom configured NetBSD kernels, *but* your
point does clarify the issue even further. It's fairly clear with an
explicit naming scheme what's what just by examining the physical
ordering and/or target select switches.
> Another thing is that if we have a limit of 8 bits for the minor
> number, there can be only 32 nailed-down devices.
> The fixed disks are c0t5d0 and c0t6d0, and c1t2d0 is a SCSI floppy.
> This is a different naming scheme than AT&T mentioned earlier.
> The nibbles seem to be cct??b where cc is controller, t is target,
> and b are control bits (I've seen them used only for tapes to indicate
> no-rewind, for example). I'm not sure if the "d0" corresponds to one
> or two nibbles -- never seen it used. HP seems to use 24 bits for the
> minor number.
The AT&T naming scheme (c0t0d0s0) uses the "d0" as the LUN, and "s0" as
the slice (or partition) number allowing for logical partitioning of
physical drives just as the final letter of "sd0a" indicates the
partition number. Doe HP-UX not have such logical partitioning?
AT&T did have some scheme for adding various control bit tags to the
name, but I don't remember the exact scheme and my manuals and system
are still packed away in the garage.....
> HP-UX includes "ioscan" which will find all attached hardware for which
> drivers are in the kernel, whether or not they have device files.
AT&T SysVr3 on the 3b2 had such probe capabilities, and finally with
SysVr4 they automated everything quite a bit such that on multiuser
boot the probe would run and would create any missing device nodes.
Greg A. Woods
+1 416 218-0098 VE3TCP <email@example.com> <robohack!woods>
Planix, Inc. <firstname.lastname@example.org>; Secrets of the Weird <email@example.com>