[Ma-linux] Apprehensive about HW
Eric Dantan Rzewnicki
eric at zhevny.com
Wed Jan 31 22:51:50 EST 2007
On Wed, Jan 31, 2007 at 05:57:35AM -0500, Kevin Dwyer wrote:
> On Tue, Jan 30, 2007 at 05:23:11PM -0500, donjr wrote:
> > On Tue, 2007-01-30 at 08:19 -0500, Johnson, Steve (NIH/OD/ORS) [E]
> > wrote:
> > > >> I thought it was the BIOS, but I could be wrong.
> > > My question on this was the capabilities of the chip in the keyboard.
> > > In other words, while it is easy explain how BIOS or the kernel
> > > could send morse code, are the Num Lock and Caps Lock lights
> > > controllable from the CPU, from the bus?
> > YES, each of the Num, Caps, Scroll lights can be turned ON or OFF
> > depending on what value you set the byte at memory address 40:17 to.
> > See: http://maven.smith.edu/~thiebaut/ArtOfAssembly/CH20/CH20-1.html
> In fact, whether the lights respond to Caps Lock, etc, is an indication
> of how locked up the kernel is.
I should add that in my case I was able to reboot with alt-sysrq.
( I think ... I'm seeming to recall that it was the middle of the night
so I can't be entirely sure I'm remembering the incident accurately. )
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