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Date:      Tue, 25 May 1999 12:34:57 -0400 (EDT)
From:      Thomas David Rivers <rivers@dignus.com>
To:        rivers@dignus.com, terry@program-products.co.uk
Cc:        freebsd-questions@freebsd.org
Subject:   Re: console terminal server and power loss
Message-ID:  <199905251634.MAA07355@lakes.dignus.com>
In-Reply-To: <eaeutt9zj.fsf@program-products.co.uk>

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> 
> Thomas David Rivers <rivers@dignus.com> writes:
> >  Personally, I've only had one power supply fail on a PC, and that's
> >  because a screw on the fan came loose, fell down, and shorted it out
> >  (what a smell.)   But - it can certainly happen.  You may be over-engineering
> >  though...
> 
> Its probably overkill but I'd rather get it right than pay the
> consequences later.
> 
> >  Here's another question - can you configure the sun Boot proms
> >  not to drop into the monitor on a <break>?   I'm not sure if you
> >  can or can't - and - if you did, how would you enter the monitor?
> >  (Maybe another character, like <cntrl>-@?)  
> 
> I've not found anything along those lines but will keep on looking.
> 
> >  But - now that I think about it; I've got a Sun here who's console
> >  is a serial console connected to a FreeBSD box... I can turn the
> >  FreeBSD box on-and-off without affecting the Sun box... so, it
> >  must be doable somehow (this is an old Sun IPC which has the older
> >  boot monitor.)  Maybe mine is set up in a nice way.  You may want 
> >  to look at the OpenBoot 2.x Command Reference Manual.
> 
> Great, at least its possible.  What serial card are you using in that
> box?  I've tried a couple of 16450s and 16550As both of which send a
> break when powered down. 
> 
> I've yet to dig deeper into the OpenBoot manual but will do so
> overnight.
> 
> >  I just tried it - I can kermit in to the box, and do a break; the
> >  machine drops into the monitor....  Something is going on, but
> >  I'm not sure what (maybe the Sun only "listens" to the break
> >  if CD is on?)
> 
> I've tried various combinations of ttya-ignore-cd and ttya-rts-dtr-off
> without luck.  Could you send me you eeprom settings?  Maybe there's
> something I haven't spotted.
> 
> My hope now is that there is a serial card out there which will leave
> the circuit open when the power it dropped rather than dragging the
> line down to zero.  Any takers?
> 
> Cheers,
> Terry.
> 

 Well - my serial card is nothing special - a cheapo 16450...

 I think the difference must be on the Sun side - as I'm quite confident
 powering down my PC would be equivalent to a break.  The sun must
 recognize the absence of power on the 232 (say, dropping TR, or CD)
 as something different than a break.

 Here's a log of me using kermit to drop into the Sun OpenBoot monitor
 and doing the printenv to get the settings...  I didn't see anything
 "magical" in there.

	- Dave Rivers -


Script started on Tue May 25 12:31:49 1999
Warning: imported path contains relative components
You have mail.
lakes# kermit
C-Kermit 5A(190), 4 Oct 94, for FreeBSD
 Copyright (C) 1985, 1994,
  Trustees of Columbia University in the City of New York.
Type ? or HELP for help.
C-Kermit>set line /dev/cuaa01
C-Kermit>set speed 9600
/dev/cuaa1, 9600 bps
C-Kermit>c
Connecting to /dev/cuaa1, speed 9600.
The escape character is Ctrl-\ (ASCII 28, FS)
Type the escape character followed by C to get back,
or followed by ? to see other options.

sun console login: Type  'go' to resume
ok printenv
Parameter Name        Value                          Default Value

selftest-#megs        1                              
oem-logo                                             
oem-logo?             false                          false
oem-banner                                           
oem-banner?           false                          false
ttyb-mode             9600,8,n,1,-                   9600,8,n,1,-
ttya-mode             9600,8,n,1,-                   9600,8,n,1,-
sbus-probe-list       0123                           0123
fcode-debug?          false                          false
screen-#columns       80                             80
screen-#rows          34                             34
use-nvramrc?          false                          false
nvramrc                                              
boot-from-diag        le()vmunix                     le()vmunix
boot-from             sd(0,2,0)                      vmunix
auto-boot?            true                           true
watchdog-reboot?      false                          false
input-device          keyboard                       keyboard
output-device         video                          video
keyboard-click?       false                          false
More [<space>,<cr>,q] ?                         keymap                                               
sunmon-compat?        true                           true
security-mode         none                           none
security-password                                    
security-#badlogins   0                              
sd-targets            31204567                       31204567
st-targets            45670123                       45670123
scsi-initiator-id     7                              7
ttyb-rts-dtr-off      false                          false
ttyb-ignore-cd        true                           true
ttya-rts-dtr-off      false                          false
ttya-ignore-cd        true                           true
hardware-revision                                    
last-hardware-update                                 
testarea              0                              0
mfg-switch?           false                          false
diag-switch?          false                          true
ok go

sun console login: 
(Back at lakes.dignus.com)
C-Kermit>quit
lakes# 


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