Re: sparcstation serial consoles

doofus <tumbleweed@xxxxxxxxxxxx> wrote:
On 7 Feb, 17:33, Darren Dunham <ddun...@xxxxxxxxxxxxxxxx> wrote:
doofus <tumblew...@xxxxxxxxxxxx> wrote:
I understand that if no keyboard is present on a sparc, it will fall
back to ttya as an i/o console.

If the configured 'input-device' isn't present, then it will fall back
to ttya.

Perhpas I was unclear here. By 'it', I meant that the hardware will
select ttya for the console.

Is it possible to have serial console access simultaneously with a
proper keyboad console attached? Even on workstations it would be
useful to have remote console access for emergency situations.

Keyboard attached, yes. Keyboard console, no.

Hmm. I don't understand. Is it not the case that if a keyboard is
attached then that's the console, no choice?

No, untrue.

You can have a keyboard attached (and used as a system terminal), but
have the console be on ttya.

There is only one "console", which is determined by the OBP at boot
time. All boot messages and OBP interaction go there.

If there can fundamentally only be one console on one machine then I
guess answers my question.

There is only one location for the console, and it's managed by the
hardware/OBP. You can redirect console messages to other devices after
the OS is running, but you cannot use those other devices to interact
with the OBP (abort, give boot commands, etc.)


You can attach a keyboard and use it on the machine while Solaris is
running for normal user logins, but you cannot use it as a console if
ttya is the console.

Confused again... I thought that if OBP input-device is set to ttya
then there's no point in attaching a keyboard because it won't work.

Untrue. The "console" will not use it. But after the machine is
booted, the OS can use it. For instance, you'd run 'dtlogin' and could
log in on the machine. What you could not do would be to press 'stop-A'
and get control of the OBP.

I think my question could have been phrased better:

1. Is it possible to have simultaneous keyboard and ttya access to the
same workstation?

Yes. Part of the confusion may be the term 'console'. On SPARC
solaris, that is a special device handled by the OBP. For general login
devices, I prefer the term 'terminal'.

2. If so, which one will be the system console, and can this be
overridden/manually configured?

Whichever (one) device you want.

Your last paragraph suggests the answers to be "yes" and "which one is
the console is determined by OBP input-device".

Correct.

But the device that isn't the console may require some additional
configuration within Solaris to be useful.

As an example, most serial devices do not run terminal logins. You'd
need to configure one for login on ttya when it is not the console.

Or, (as is more common), if the console is on ttya, then I'd want to
reconfigure /etc/dt/config/Xservers so that it knew it was running on a
device without an underlying tty. (there's an example of this near the
top of the file. If the file doesn't exist, make a copy from
/usr/dt/config/Xservers first).

--
Darren Dunham ddunham@xxxxxxxx
Senior Technical Consultant TAOS http://www.taos.com/
Got some Dr Pepper? San Francisco, CA bay area
< This line left intentionally blank to confuse you. >
.

Relevant Pages

  • [SUMMARY] console i/o
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  • Re: sparcstation serial consoles
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