Mark
Thanks for your comments. You clearly have a far deeper knowledge of electronics than me and understand implicitly the problems, what chance have I and people like me when it comes to selecting the right computer?
Our friend i2i is concerned that my proposed computer would not be viable because there are many different types of machine. Well I would respectfully suggest that at the moment there are not only a wide variety of different machines but we are trying to control them with a wide variety of old computers which were not designed with this application in mind in the first place.
I am fortunate to have experienced how smooth, fast and accurate commercial CNC machines are, and I have no doubts Micro CNC machines can be virtually as good without spending huge amounts of money in the process. I will also bet that within our midst there are people who given a piece of paper and a pencil could formulate the specification for such a computer and the source of the necessary components before I could make them a cup of tea.
Currently we benifit from pretty good small machine tools and very good control software (Mach3) can we not complete the chain with a first class computer? One day and I hope sooner rather than later, we will look back and wonder why we tolerated second class time expired electronics for so long.
How about it guys, who's up for the challenge?

Geoff Vaizey