Imagine going back in a time machine to 1976, when I fi rst started to use Unix. You fi nd me and ask for a tour of the Unix system I am using. To your surprise, you see fi les, directories,...

Imagine going back in a time machine to 1976, when I fi rst started to use Unix. You fi nd me and ask for a tour of the Unix system I am using. To your surprise, you see fi les, directories, subdirectories, a working directory, a home directory, special fi les, links, inodes, permissions, and so on. You also see all the standard commands: ls, mkdir, pwd, cd, chmod, cp, rm, mv, ln and find. Indeed, you notice that virtually every idea and tool you learned about in this chapter was developed more than thirty years ago.

What is it about the basic design of the Unix fi lesystem that has enabled it to survive for so long and still be so useful? Is this unusual in the world of computing?