[lkml]   [2001]   [Jan]   [27]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: Linux Post codes during runtime, possibly OT
Rogier Wolff wrote:
> H. Peter Anvin wrote:
> > Followup to: <>
> > By author: "Ian S. Nelson" <>
> > In newsgroup:
> > >
> > > 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.


<> at work, <> in private!
"Unix gives you enough rope to shoot yourself in the foot."
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to
Please read the FAQ at

 \ /
  Last update: 2005-03-22 13:24    [W:0.098 / U:9.848 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site