He convinced his own government to bankroll his 'Difference Engine,' as he called it. But after ten years and some £17,000 of public money, Babbage's machine, which was designed to tabulate logarithms and trigonometric functions, remained only half built. So he did what any good visionary would do: He scrapped the plans in favor of something more ambitious.
The Analytical Engine, which, like the Difference Engine, existed mostly on paper during Babbage's lifetime, was envisioned as a general calculating device. The user would input punched cards into the machine, which would be processed by rotating barrels. The machine would output to a printer, a plotter, or a ringing bell. (Babbage was inspired by the Jacquard loom, which used punched cards to "program" certain weaves, such as a brocade or a damask.)
The design of the Analytical Engine is nothing like that of today's MacBook, but it has all the basic architecture. It distinguished between program memory and data memory. It had a separate input/output unit. It accepted conditional "if/then" expressions.
Of course, the average laptop is millions of times more powerful. According to John Graham-Cumming, a British programmer and writer who is seeking to build a real-life Analytical Engine, the machine would have 675 bytes of memory and a clock speed of 7 Hz. Graham-Cumming told the BBC that if completed, Babbage's machine would be "about the size of a small steam train."