Rebooting The World?

Kristopher Johnson asks: "As things are now, it is pretty easy to develop software for new hardware platforms. Just write a cross-compiler on an existing platform, and then copy the binary to the new system. New hardware is designed and manufactured using software running on existing hardware. So what if we had to start over from scratch? Say some cataclysm occurs that fries all microprocessors and scrambles the contents of all existing ROMs, disks, CD-ROMs, and any other machine-readable media in all computers. And the same fate falls on all high-tech manufacturing equipment. What would be the fastest way to 're-computerize' the world? What would we do differently if we didn't have fifty years worth of legacy systems to continue maintaining?" It's an interesting thought, and one that I tend to not spend much time worrying about. For those of you who have, however, how do you think humanity would recover from a catastrophic loss of all electronic technology? My personal experience is that if something like this were to occur, we would not recover very quickly, but I'm not as optimistic as I was a few years ago. Maybe some of you can paint a better picture.