SUMMARY: booting a 20 headless

From: Kain, Becki (B.) (
Date: Wed Apr 05 2000 - 12:49:11 CDT

Here is my original message:

This one has me stumped. I have a sparc 20 and whether I leave the frame
buffer card in or not, I cannot get it to boot to a serial terminal. I have
the null modem cable on there, the hyperterm is 8 none 1, no flowcontrol,
there is no keyboard connected, nothing connected to the onboard graphics
card, yet it will not write to the terminal. I thought this should work.
the output device in the prom *is* set to the screen, but that is the
default. According to Sun, this should work. So what am I doing wrong?

and thanks to all who answered. there were basically a few different
answers. Make certain you have a null modem cable (it is), make certain the
output is set to ttya(it's not, but it needs to be), you may need a splitter
(I didn't):

Buddy Lumpkin
Make sure there is no frame buffer
setenv diag-switch? true
then turn the power off, unplug the keyboard and power it back on. Note that
you need a NULL-MODEM serial cable for this to work. Turning on the diag
switch is actually not necessary but then it doesn't matter whether you have
the video device configured special or not, you should ALWAYS get tons of
output to port A with the diag switch on.

If it does decide to use your frame buffer anyway, you will see a message
right before the data stops going to the serial port (usually right after
the banner that shows hostid, ethernet address and the serial number.

Steve Tidy []
I'm pretty sure that you will have to set the output device to be ttya. We
had a similar problem but in reverse (the machine had been connected to a
via the serial ttya port), and when we subsequently connected a monitor we
to reset the prom to get it to boot.

John Malick []
You may want to check the eeprom settings for ttya and make sure they are
also set for the defaults of 9600, 8, N, 1 . Make sure the terminal is set
at 9600 instead of auto detect. The eeprom settings for ttya-rts-dtr-off
also should be checked as well as ttya-ignore-cd.

You may want to purchase a serial port splitter cable. Although
attaching a serial cable to the A/B port will give you serial A, I've seen
issues from time to time when a serial splitter is not used. The sun part
number for the serial splitter is X985A and will provide an A and separate
B cable ends. Hook up the terminal to the A end.

Mark Sherman []
don't know what prom level you're running, but did you check to see if obp
variable ansi-terminal? = true ?

Charles M. Gagnon []
Did you check all the PROM settings for the serial ports:


Make sure the speeds match (terminal vs. PROM). I know Suns
can be annoying with this.

Make sure you don't have two nulls on there by mistake and
make sure the cable is good AND the null adapter is good.

You're right about the screen thing, that how it's suppose to
be. When suns boot, if nothing is connected to the keyboard,
the use ttya as a console.

Carsten B. Knudsen []
  It looks to me as if you did everything you ought to; We have a
headless Sparcserver 20 (never had a framebuffer in it) and it runs like a
charm. OTOH, I did see something like what you describe on a UE2 and it
turned out to be a roasted serial port; did you check if there's any life
on the ttya line once the system is up and running? To use ttyb instead,
change OPB "input-device" and "output-device" to "ttyb". You also need an
"A/B splitter cable" - buy one from Sun or have one made yourself. The
pinout of the DB25 port is as follows, with port A connections in the
usual places and port B on otherwise unused pins:

pin function pin function
--- -------- --- --------
2 TxD A 14 TxD B
3 RxD A 16 RxD B
4 RTS A 19 RTS B
5 CTS A 13 CTS B
8 DCD A 12 DCD B
20 DTR A

Doetzl Joseph []
        Try the following:

                eeprom output-device=ttya
                eeprom input-device=ttya
                eeprom ttya-rts-dtr-off=false
                eeprom ttya-ignore-cd=true
                pmadm -p zsmon -r -s ttya

        See sun infodoc id 16093 for more info.

Robert Hayne []
Sullivan, Rich []
Nandkishor Kale []
Will Lowe []
Richard Bond []
Todd M. Wilkinson []
J.J.Bailey []
Seth Rothenberg []
Richard Bond []

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