On Wed, 1 Jul 1998, Andrew James ROBBIE wrote:

> Is having localtalk disabled important? I have a LaserWriter
> Plus, which needs localtalk, but the printer is the only thing
> connected. It never caused any problems under 7.1 (not that I
> was networking netbsd to anything anyway).

If you just have a laserwriter on the wire, then LocalTalk shielding will
be not very important. Also, with changes I've made to the serial code, I
don't think it will be very necessary for booting anymore.

The problem was that MacOS would leave the serial chip receiving LocalTalk
when we got the machine. Whenever a packet came in, we generated an
interupt which the serial code was not in a position to deal with.

Currently, we disable the ability to generate new interupts. A recent
change also clears any already-pending interupts (that's where the crashes
after zsc0 attach came from).

the reason you're failryl safe with just a LaserWriter is that the
LaserWriter only initiates packet transmission when it gets turned on (it
checks its address). At all other times, it's responding to other
requests, which won't get sent if you're not using LocalTalk.

On LocalTalk nets with a router, the router periodically sends out
messages indicating its presence. If they came in during boot, they'd kill
the kernel. Thus the shielding.

Take care,

Bill