>> Expert C Programming . This book is fantastic because it will bring your attention to what happens under the hood in a very entertaining way. I am not a C pr

>> Expert C Programming . This book is fantastic because it will bring your attention to what happens under the hood in a very entertaining way. I am not a C programmer nor was trying to become one. Just trying to be familiar with low level programming and computer internals in general. But I enjoyed reading the book a lot. One of the the stories I remember is about the programming contest at Carnegie-Mellon University. The rules were simple that the program had to run as fast as possible and the program had to be written in Pascal or C. Here are some paragraphs extracted from the book about the result. “The actual results were very surprising. The fastest program, as reported by the operating system, took minus three seconds. That's right—the winner ran in a negative amount of time! The next fastest apparently took just a few milliseconds, while the entry in third place came in just under the expected 10 seconds. Obviously, some devious programming had taken place, but what and how? A detailed scrutiny of the winning programs eventually supplied the answer. The program that apparently ran backwards in time had taken advantage of the operating system. The programmer knew where the process control block was stored relative to the base of the stack. He crafted a pointer to access the process control block and overwrote the "CPU-time-used" field with a very high value. The operating system wasn't expecting CPU times that large, and it misinterpreted the very large positive number as a negative number under the two's complement scheme. “