All being well, IBM plans to enter its Watson computer into the US gameshow Jeopardy! in 2010. In order to win, the machine will not only have to understand the questions, but dig out the correct answers and speak them intelligibly.

After all the broken promises from the over-optimistic visionaries of the '50s and '60s, are we finally moving towards a real-life HAL? If we are, why has it taken so long?