Gorshr{i, not Gorshr{e. That is all.

http://en.wikipedia.org/wiki/Frank_Gorshin


i[larry]

"Superman Returns The Videogame"? That doesn't sound like a compelling premise for a videogame. Does he have to wait in line long?

Dude, that "Half-Life" on the iPod Nano was *very clearly* an original DOOM mod that makes it look like Half-Life. While it's neat that they have DOOM running on the iPod, it is supremely lame that this guy lied and claimed it was Half-Life.


/larry/

I've been a Windows programmer since 1991, and I've been using Windows-NT-based OSes since they were first released... 1993 iirc. (Windows 2000 and Windows XP are NT-based.) And I can safely say your diagnostician is living in a fool's paradise.

Theoretically, neither BF2 nor any other program should be able to BSoD the system. The design of Windows NT should preclude that. But there are two ways in which it could.

First of all, in Windows NT, programs run in "user-space", not in "kernel-space". This uses facilities on the CPU (user space is "ring 3", kernel space is "ring 0") to ensure protection. Code in user-space isn't allowed to do a lot; if it tries to do something malicious, it gets stopped cold. In order for a well-behaved user-space program to do anything *interesting*, like open a file or play a sound, it has to ask the kernel to do it; because the kernel is in "ring 0", it can do anything it likes. So theoretically the only way a user-space program could crash the OS is by asking the kernel to do something that results in the *kernel* crashing. A malicious request with a deliberate buffer overflow, or just a bug in the kernel. This isn't supposed to ever happen, as the "take requests from user-space" part of the kernel is ten years old and battle-hardened. Honestly I doubt this is the problem; this is what your diagnostician pal is thinking of when he says it's "not possible".

But there's a second concern. Since the original NT, many drivers have been moved out of "user space" to "kernel space". Windows NT's original design was "microkernel"-ish, in that *every* device driver was forced to live outside the kernel. That way, again, it wasn't *possible* even for bad *drivers* to crash the system! (You can perhaps appreciate in what ways this is a good design.)

However, in order to actually get anything *done*, you had to suffer a large number of "ring transitions", where you go into and out of the "kernel" dozens of times in order to get anything done. For example, if BF2 wants to send a texture to the card, it calls the kernel and says "send this to the graphics card". We've now gone from ring 3 to ring 0, which I'll mark as R3->R0 henceforth. The kernel now turns around and calls the graphics driver (R0->R3), which says "ah, yes, to do that you need to poke at the card *this* way (R3->R0 and back) and *that* way (R3->R0 and back) and so on.

All those ring transitions add up pretty quickly. In the world of application programming, they are shockingly slow, and you wind up hitting a *lot* of 'em very quickly. So, over time, the NT group has been moving more things out of user-space and into kernel-space. Graphics drivers were moved into the kernel with NT 4.0, back in the late-ish 90s.

And guess what *that* means. Now your graphics driver runs at ring level 0, in kernel-space, so it can do anything it wants. Including crash your whole OS. Graphics drivers are notoriously buggy; they are thrown together to support a new card, and banged on enough until they work relatively well, then shipped. Everyone here has seen more than their share of graphics-driver bugs.

I find it *very* easy to believe that BF2 is calling the graphics driver in such a way that it incurs a BSoD'ing graphics-driver bug.

I solved 8 ("fenwick"), but with a trick. I'm not 100% sure it's supposed to work this way, but...

R D L U R D
and look! we stopped! I think it's because we went slightly into the red thing. From there,
R U R D L

I'm stuck at 17, "hotwater". Working backwards from the exits hasn't helped; as far as I can tell there's no way to finish the level. Anyone have a bucket of clues for me?