Introduction

In the physical world, entropy is the unavoidable consequence of the 2nd law of thermodynamics. In theory the 2nd law doesn't hold in cyberspace, but in practice it does. Information that's stored in computers "rusts" at least as fast as information stored in real-world media. I'm reminded of this every time I walk through the cemetery down the street from my house: many headstones manufactured in the 17th century still convey the information that they did when they were new. On the other hand, when my Mom "upgraded" to Windows '95 a few years back she found that all of the documents she had written in her low-end microsoft word processor were completely illegible on the new version of the high-end office suite, even though only 5 years had passed. She was lucky to be computer-naive - she lost nothing since she had printed all of the documents on paper. If she had used the computer the way that the manufacturers wanted her to she would have either lost the documents or I would have spent a lot of time scraping the data out of them.