Earlier quoted context omitted.
They built a system where any data set can be pushed in, joined with the rest of the data, and then automatically made inferences off of for trading.
In what timescale though? There are huge differences between the timescales of "realtime" (say HFT), a second later, a minute later, an hour later, a week later and so on. Do they operate at all of them? I have no specialist knowledge, btw, I'd sincerely like to know!
If memory serves, in the aforementioned podcast Gregory mentions that the RenTech generally holds most things for a few days (sometimes a few hours). However, they don't engage in HFT or HFT-like trading. This was surprising to me as I assumed it was all reasonably short holdings (relatively speaking), although I knew they weren't a pure HFT firm.
I also seem to recall Gregory mentioning there's some kind of running joke internally that their trading systems aren't nearly as good as they should be (or like what you would find at HFT firms). Given the intellectual and monetary heft within RenTech perhaps that's a bit of false modesty on their part.
I'll be interested in reading Gregory's book as he does seem to have put together a lot of novel information on RenTech. However, he does seem to suggest that very little of the day-to-day workings of the firm will be explored, which would obviously be immensely interesting.
EDIT: RenTech has several funds, it should be noted. Some of which still take outside capital. What I've said above may have only been applicable to the Medallion fund.