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Except that a computer can't do random. It's NEVER purely random. All a computer can do is pseudo-random. No matter which algorithm you take, if you initialize it with the same seed, you will always have the exact same sequence of numbers, no matter how many of them you want to take.
And of course, not all psuedo-random number generators are equal. There are lots of trade offs being made regarding complexity, time, memory use, sequence length, etc.
One thing for sure, is that for anything a little bit serious, you should never ever use the rand() function from a unix system it's just straight awful (bias towards low numbers). urandom doesn't have that specific problem, but it's not true random either. Of course as long as it does the job, it doesn't matter all that much.
That being said, as someone who's been on the wrong end of a roller who's been angry for quite some time (20d20, 2 rolls above 11...) I can't help but have my doubts. That being said... We're the type of people who would just change a die on the table as if it magically solved everything despite knowing perfectly well that it doesn't, so...