Never heard RenTec described that way, the only information that seems to be out there is that they use much simpler algorithmic techniques than people imagine, mainly just linear regression. Whatever unique insight they have, it's more likely to be based on pure mathematics than cutting edge algorithms theory. Also, they were not the first quant fund.

Unix was cutting edge OS theory? I mean, it was Bell Labs, and they were probably the premiere research facility in the world at the time, but my impression is that the trick on Unix was how small they were able to squeeze it, not that it was pushing theoretical boundaries.

Can you point me to any aspects of Unix that were theoretically new?

What we take for granted today was once brand new and hard won.

True. But what was new in Unix? What specifically?

Multitasking

Didn't Multics have that? I mean, Multics never went anywhere, but the theory wasn't new to Unix, was it?

Back then, Multics was designed to run on expensive and specialized proprietary hardware where as Unix could run on a variety of cheap computers.

One can say the philosophy behind Unix was new. I'm sure that's why modular and micro kernel designs caught on.