Re: Linux Post codes during runtime, possibly OT

["H. Peter Anvin" <hpa@transmeta.com>]

Rogier Wolff wrote:
> 
> H. Peter Anvin wrote:
> > Followup to:  <3A709E99.25ADE5F6@echostar.com>
> > By author:    "Ian S. Nelson" <ian.nelson@echostar.com>
> > In newsgroup: linux.dev.kernel
> > >
> > > I'm curious.  Why does Linux make that friendly 98/9a/88 looking
> > > postcode pattern when it's running?  DOS and DOS95 don't do that.
> > >
> > > I'm begining to feel like I can tell the system health by observing it,
> > > kind of like "seeing the matrix."
> 
> > It output garbage to the 80h port in order to enforce I/O delays.
> > It's one of the safe ports to issue outs to.
> 
> Yes, because it is reserved for POST codes. You can get "POST
> debugging cards" that simply have a BIN -> 7segement encoder and two 7
> segment displays on them. They decode 0x80. That's what it's for.
> 

Again, if you want to change it, find another safe port, test the hell
out of it, an *PUBLICIZE IT* so noone will use it in the future.

	-hpa

-- 
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