I plan to use my already existing file server to start.
I wouldn’t consider SATA a high-spec machine. Almost any computer will have it. I’m sure there are low priced boards out there that can support such a thing. Also, the least expensive hard drives will be SATA.
What is your particular application? If you are building a dedicated farming box, I would assume your goal is to achieve the highest rate of safecoin production for the least amount of capital investment and maintenance.
As you said we have no idea what will affect safecoin production rate, so this is all speculation at this point.
I hope there will be a difference between USB based storage and SATA based storage. USB will add at least 10ms of latency. If the network can’t tell the difference in 10ms access times, I fear it will be a slow network indeed. I hope safecoin production rates will be affected by such things.
Maidsafe is the ultimate random access scenario. We will be constantly reading/writing 1MB blocks off the drive. Sustained read/write performance won’t matter at all (your hard drive will never be slower than your network). What will be important is how fast you can find and begin streaming. So, you will need just enough RAM to cache whatever metadata the node needs to keep around, and just enough CPU to handle the communication and encryption efficiently. The important thing will be latency, how fast can you turn a request around into a stream of data.
In the future I can see farming specific node software being built with integrated filesystem drivers. A lookup table between the maidsafe ID and the hard drive block will be stored in RAM or an SSD. The goal would be to reduce the hits to the hard drive to the bare minimum, only calls to read/write chunks should ever make it to the slow bulk data medium.
If I was looking to build a farming box now, I would look in the media-center space. My specs would be:
Small, low power, efficient PSU - electricity input will be important
Internal bays for storage - no need for expense of an external box for hard drives
SATA - low latency and cheap
ethernet - 10/100 will do unless I have a Google fiber account or something
hard drive(s) - find the cheapest per GB. The question will be how much space is best
RAM - depends on what the optimum cache size ends up being
bandwidth - the most important factor, but not relevant to building the actual box