Many of the items discussed in this pre-article seem way overkill for what the author seems to be trying to do. It doesn't take much to create an account with a reputable broker like Interactive Brokers that has a good live API for auto-trading (and support paper trading to test your code without using real cash). There are no upfront fees on many brokers and the commission is often minimal depending on the transaction. eTrade has similar APIs. Historical data is available at minimal cost through a sites like eoddata.com. Also, especially if you're just starting and experimenting with formulas, using your personal laptop/desktop with a live feed from IB is more than enough to act on live tick data for the symbols you're interested in.
You can't do ultra low latency trading on IB or any of the discount brokerage houses. Essentially, your order goes through their system before it goes out on the broad market, and that (time) cost is orders of magnitude larger than the internal system cost. Also, the (economic) costs of doing business with that type of broker are comparable to to the profits.
There are difficulties with simulating at this level, and I will go into this later, because the quality breaks down. Many ultra low latency trades involve some sort of rebate capture (profiting off of the fact that the exchange gives you money if you provide liquidity to the markets), and that requires some sort of model for how the rest of the market would react to the presence of your extra liquidity.
