Windows kernel once had code to deal with gamma rays

Posted on Wednesday, Nov 21 2018 @ 10:19 CET by Thomas De Maesschalck
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Here's a funny story from the Microsoft MSDN blogs, a Windows developer explains the operating system's kernel once contained code to deal with stray gamma rays! For a brief period of time, this code was added to the kernel at the request of a processor maker. Three weeks later, the INVD instruction was commented out, but it's still part of the Windows kernel.
At one point, the following code was added to the part of the kernel that brings the system out of a low-power state:

;
; Invalidate the processor cache so that any stray gamma
; rays (I'm serious) that may have flipped cache bits
; while in S1 will be ignored.
;
; Honestly. The processor manufacturer asked for this.
; I'm serious.
;
invd


I'm not sure what the thinking here is. I mean, if the cache might have been zapped by a stray gamma ray, then couldn't RAM have been zapped by a stray gamma ray, too? Or is processor cache more susceptible to gamma rays than RAM? The person who wrote the comment seems to share my incredulity.

Less than three weeks later, the INVD instruction was commented out. But the comment block remains.


About the Author

Thomas De Maesschalck

Thomas has been messing with computer since early childhood and firmly believes the Internet is the best thing since sliced bread. Enjoys playing with new tech, is fascinated by science, and passionate about financial markets. When not behind a computer, he can be found with running shoes on or lifting heavy weights in the weight room.



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