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Re: Problem with "Happy Meal" drivers



I am reasonably certain this doesn't happen on (some?) sparc hardware.  I've
had an Ultra30 plugged into our E450 via serial, and when I rebooted it,
I don't recall finding the E450 at PROM later.

I could be wrong, of course.


On Sun, Jan 11, 2004 at 03:54:17AM -0800, ndade@jasiri.com said:
> Date: Sun, 11 Jan 2004 03:54:17 -0800
> From: ndade@jasiri.com
> To: bath66 <bath66@bath66.homeip.net>
> Cc: Andrew Sharp <andy@ccpu.com>, debian-sparc@lists.debian.org
> Subject: Re: Problem with "Happy Meal" drivers
> User-Agent: Mutt/1.3.28i
> X-Spam-Status: No, hits=0.3 required=4.0 tests=NO_REAL_NAME autolearn=no 
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> 
> On Sun, Jan 11, 2004 at 08:58:17AM +0100, bath66 wrote:
> > "Andrew Sharp" <andy@ccpu.com> was quoted as saying by some wrong mail agent
> > operated by Mr. bath66 who should know better
> > >
> > > Before you turn off the PC that is connected to the Sun's serial
> > > console, remove the cable from the sun.  That way, the sun will stay
> > > running and you won't have these problems.
> > >
> > Thanks for the conseil .. It work now ... but can you explain me why ?
> 
> A break signal on the sun serial port drops it into the openboot prompt.
> 'go' restarts it where it left off.
> 
> In rs232 a break is signaled by holding the line low for longer than
> 10 bit times (therefore it cannot be a valid byte b/c a valid byte
> would have ended with a high stop bit at the 9th bit[1]).
> 
> Some PCs inadvertently drive TX low for that long as power goes down.
> There isn't much you can do; I even tried lowering the baud rate
> and even as 1200 the PC's signal was long enough to act as a break.
> 
> -Nicolas Dade
> 
> [1] assuming 8N1; the principal is the same with other data settings---
> a break is unambiguously not a data transfer
> 
> 
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-- 
Mike Edwards <sauron-debian-sparc@psychology.rutgers.edu>
System Administrator
Psychology Department, Rutgers University, Newark campus
973-353-5440 x246



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