When I have seen a VGA monitor display white text on a black background,
it has often meant that something had mistaken it for a monochrome monitor.
White-on-blue may have been chosen to demonstrate that the colour video
hardware is not the problem.  [I do have VCRs which put out a blue screen
when they have no other image available, so it may be a traditional video
default.]

  One of my favourite hacks for Windows 98 was a registry hack to change the
colours used by the BSOD code.  So far as I know, no-one has duplicated this
for NT/2K/XP.

  Failures which simply scramble the video RAM contents are not unknown, but
they tend to be on-card failures of the video hardware and not messages from
the OS kernel.


  I believe the BSOD code uses the legacy BIOS CGA text output routines and
so does not rely on the video card driver or the Windows screen-management
code.
  Many kernel functions are invoked by a signal from the processor that an
instruction cannot immediately be executed.  For instance, a "page fault" is
signalled by the CPU when a reference is made to a virtual address that
doesn't currently map to an address in physical RAM.  Normally this invokes
a kernel routine that will select an unused area of physical RAM (or de-
allocate one in use if necessary) and read in the needed segment of the swap
file, update the logical-to-physical translation table, and then tell the
CPU to retry the memory access which should now work.
  Very often, a BSOD will result when the CPU calls for this kind of kernel
assistance from within one of these kernel routines, or when an invoked
kernel routine cannot perform its task.  For instance the "page fault not in
paged region" BSOD results when the required logical address isn't in the
swap file, either.

David Gillett



On 1 Jan 2006 at 14:56, Dean Kukral wrote:

> I was reading Peter's question about a possible failing video card,
> and it got me wondering:  Why is it a **blue** screen of death when
> your computer crashes?
>
> I have had black screens - that makes sense.  (SP2 caused them.)
>
> But why Blue?  It seems that if the computer crashes, then garbage
> should be going to the video card and GIGO!
>
> Do video cards put out a blue screen by default when the input
> directions make no sense?  Then, a blue screen would seem to make the
> video card less of a likely culprit when there is a system crash, as
> it is doing what it is supposed to be doing.
>
> Dean Kukral

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