A bit of advice, orthogonal to whatever PG's answer is: I too am applying with a large hard problem, but nonetheless I'm going to have a demo. It's a throwawa

A bit of advice, orthogonal to whatever PG's answer is: I too am applying with a large hard problem, but nonetheless I'm going to have a demo. It's a throwaway prototype that, if I tried to use it as production code, would scale to about ten users before the server fell over. See if you can figure out a way to do the same. If you're doing a put-your-favorite-UNIX-command-on-the-web type startup, just make a web-based frontend that actually invokes that UNIX command to do its processing.