Subject: Re: zs driver patch.
To: Ron Roskens <roskens@Elfin.Net>
From: Simon J. Gerraty <>
List: port-sparc
Date: 10/03/1999 23:16:53
>> > The included patch updates the the zs driver, such that you need to key in
>> > a sequence ( BREAK, any char, BREAK, any char, BREAK ) before it will drop
>> > to the debugger/prom.

>Well, I had to get used to sending this sequence at a place I worked at.
>The client had hacked the zs driver in solaris to require this before

BTW there is a Sun consulting special which essentially does the above - make
the prom require a sequence of chars rather than a simple break.

Given the fact that devices sending a break as they power down is not
at all uncommon, your patch is probably a good idea.

>dropping the machine down. Something about terminal servers and serial
>lines was the reason they added this feature.

Or crappy new PCI based multi-port serial cards from Sun.
Where I work, we have used many of the s-bus 8 port serial cards in
firewall management stations to provide console connections to all the 
routers, switches and other bastions.

When we started using 450's for the management station, we discovered that 
the PCI based 8 port serial cards (made by digi board btw), had the 
"feature" of sending a break to all the consoles of all those devices
if the managment station was powered down.

We looked at the consulting special from Sun, and decided to switch 
to using a terminal server off a private ethernet at the back of 
the management station.

We've had lots of fun in the past with certain terminals sending a break 
when powered off.  We had to tape over the on/off switch to stop thrifty
people walking through the machine room doing us a favour by turning
off the terminal :-)