Byron.Servies@Sun.COM wrote:

> Isn't this the serial dtr(?) release causes the kernel to go into the 
> debugger?  I asked this years ago and was surprised this legacy behavior 
> (form the early days of unix, iirc) was still there.

Not DTR release but BREAK signal put kernel into ddb(4),
and removing serial cable or reseting terminal could cause
BREAK signal. In that case, you can use the "c" (continue)
command on ddb to resume. (see ddb(4) man page)

According to <sys/systm.h> sysctl ddb.fromconsole=0 should disable
this behaivor, but maybe you could also try sysctl hw.cnmagic as
mentioned in cnmagic(9) man page, or you could simply disable
options DDB in your kernel config.
---
Izumi Tsutsui