1. The Software scientist. This is a man who takes a mathematical algorithm, performs a series of transformations on it and ends up with a program in lambda-calculus. This program is _correct_, meaning it will do what it is supposed to. Now all he needs is a lambda-calculus interpreter, a stable operating system, a computer with a proven architecture and an uninterruptable power supply.

2. The Software engineer. This is a man who thinks that if he divides the task up into small enough pieces, it will disappear and he can go back to reading news.

3. The Programmer. The programmer will listen to your requirements, sit down and actually write you a program. Unfortunately, it doesn't do what you want it to, but what the programmer thinks you _ought_ to want it to do.

4. The Hacker. The hacker will listen while you tell him what you want, say "that's easy", and type an amazingly long command line with about 30 pipes. As the line executes, you can hear the disk thrashing away with the effort of opening and closing all the temporary files.

5. The Hardware Buff. This is the guy who tries to implement an awk interpreter in discrete logic...

6. The System Administrator. While idly looking round to see what's going on, discovers a process with a suspicious-sounding name, kills it and asks you via mail what it was. This happened to me: the process was my login shell, bash!