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Re: How to tell Sun keyboard console from serial console?

Michael Dolan mtdolan@twinight.org
Mon, 20 Jan 2003 14:55:14 -0800 (PST)

On Sun, 19 Jan 2003, Greg A. Woods wrote:

> Date: Sun, 19 Jan 2003 19:32:57 -0500 (EST)
> Substitute /power-on/ for /boot/ and you're probably right.

True. If you reboot/reset from a workstation console and pull the kbd in
time... :)

> I'm not sure that's the same as knowing whether the kernel thinks it's
> "console" pseudo-device is attached to the KBD & FB or not, and I
> wouldn't want to bet on it without seeing the source....  :-)

I think "prtconf -F" will suffice for most queries, but if you want to be
sure, try this... clumbsy but functional, and you might not want to do it
in absolute mission critical environments during production hours:

# adb -k /dev/ksyms /dev/mem

wscons:		1	(workstation console, ie kbd/fb)


wscons:		0	(ttya, ttyb, rsc, other?)

I tested this under solaris7 - 9 on various workstations with kbd/fb and
servers w/o, including E10K and SFx800, results were consistent. See
wscons(7d) for more info.

It might be useful (or not) to point out that you can ensure console
output is always ttya by setting eeprom variables to such. (Caveat being
E10K, SFx800, and RSC consoles). You can serial consoles on graphical
workstations by setting the eeprom variables to ttya, ttyb or rsc and
modify your Xservers file (replace 'console' with 'none' for :0).

In addition, the consadm (1m) facility (s7 and higher?) adds support for
auxilary consoles. Besides the default console, you can add additional
consoles for output (and input up through single-user mode). You can add a
second console to a running system and attach to it read-only.

Tangent: I suppose one could build a redundant serial console solution
by having duplicate conservers and serial concentrators/cabling setups,
one attaches consoles to ttya and one attaches to ttyb. In a fashion,
Console-HA... for that occasion when you fry a serial port or trash your
primary console infrastructure. Overkill for most environments. :)