
Let me give a meaningful response: in low latency trading, the value is truly in the platform. The strategies are simple, and you can pick up a textbook (ie Aldridge http://www.amazon.com/High-Frequency-Trading-Practical-Algor...) to learn the strategies employed at that level. That being said, the traditional "sysadmin" role is oftentimes filled by people traditionally described as "developers". The roles have melded over the years.
Hence, the question you are asking really delves into the "alpha" of the platform. This is something a practicing HFT sysadmin wouldn't want to divulge (or can't because of the highly litigious nature of the industry -- take Sergey Aleynikov or Samarth Agarwal as examples of what could happen if people talk too much)
High-Frequency Trading: A Practical Guide to Algorithmic Strategies and Trading Systems http://www.amazon.com/gp/product/0470563761
Inside the Black Box: The Simple Truth About Quantitative Trading http://www.amazon.com/gp/product/0470432063
Quantitative Trading: How to Build Your Own Algorithmic Trading Business http://www.amazon.com/gp/product/0470284889
Chan 2013 Algorithmic Trading, Winning Strategies and Their Rationale
Davey 2014 Building Winning Algorithmic Trading Systems, A Traders Journey from Data Mining to Monte Carlo Simulation to Live Trading
Halls-Moore 2017 Advanced Algorithmic Trading, Bayesian Statistics Time Series Analysis and Machine Learning for Profitable Trading Strategies
Kissell 2014 The Science of Algorithmic Trading and Portfolio Management
Leshik 2011 An Introduction to Algorithmic Trading, Basic to Advanced Strategies