Watt?? A steam powered PC !!!

A UK campaign to build a truck-sized, prototype computer first envisaged in 1837 is gathering steam.

More than 1,600 people have pledged money and support to build Charles Babbage's Analytical Engine.

Although elements of the engine have been built over the last 173 years, a complete working model of the steam-powered machine has never been made.

The campaign hopes to gather donations from 50,000 supporters to kick-start the project.

"It's an inspirational piece of equipment," said John Graham-Cumming, author of the Geek Atlas, who has championed the idea.

"A hundred years ago, before computers were available, [Babbage] had envisaged this machine."

Computer historian Dr Doron Swade said that rebuilding the machine could answer "profound historical questions".

"Could there have been an information age in Victorian times? That is a very interesting question," he told BBC News.

Number cruncher

The analytical engine was designed on paper by mathematician and engineer Charles Babbage. It was envisaged that it would be built out of brass and iron.

"What you realise when you read Babbage's papers is that this was the first real computer," said Mr Graham-Cumming. "It had expandable memory, a CPU, microcode, a printer, a plotter and was programmable with punch cards.

Although other mechanical machines may predate the Analytical Engine, it is regarded as the first design for a "general purpose computer" that could be reprogrammed to carry out different tasks."It was the size of a small lorry and powered by steam but it was recognisable as a computer."

It was the successor to his Difference Engine, a huge brass number-cruncher.

"The Difference Engine is a calculator," said Dr Swade, who was part of a team that spent 17 years painstakingly building a replica. "It is not a computer in the general sense of the word."

He said that it would be "astounding" if the Anaytical Engine could also be built.

"The Difference Engine is already a legendary model, but it is dinky compared to the Analytical Engine," he said.

He said Babbage's many designs for the device suggested that it would be "bigger than a steam locomotive."

"That is with just 100 variables," he said. "He talked about machines with 1,000 variables, which would be an inconceivably large machine."

No one has built an entire Analytical engine, although various people, including Babbage's son and Dr Swade, have created elements of it.