> At work the other day I was working on a machine that had
> suspected bad memory or board, and I decided to throw in a drive with
> linux and compile a kernel to see if I could get a more informative
> message than Win95 locking up and diagnostic programs passing.
>
> I had left a POST board in to use some of the onboard diagnostics,
> and when linux was booting I glanced over at it and saw the display going
> nuts. When the machine was idle it held at 51, and when I flipped between
> virt terms it jumped to 3F and back to 51. Initalizing swap caused it to
> flash between 88 and 5 other codes so fast the LCD couldn't keep up.
> Compiling the kernel caused the same reaction only a bit slower.
>
> Does linux use 80h, as a status display or some form of
> communication channel?
>
Linux uses writes to port 80h to slow down I/O for ports who can't keep
up. The data written is what happens to be in register %al at this time,
which is certainly not very informative ;)
Gabriel.
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