.. and both happen to have strong links to Tcl :-)

Could you explain why?

Both are small projects by small teams (though I don't know how small Redis team is now). They have insane performance characteristics with rather small footprints and a wealth of functionality.

My experience is that small, dedicated teams of high-performing individuals are the only way to build tools like these. The level of architectural and design coherence starts to decrease at 5 people, and falls like a rock beyond 10-20.

The key problem is building a firewall so that such people can focus. The *organizational* problems there are hard. If you have a firewall around five people, you can't tell if:

- They're sitting at home drinking beer and watching cat videos

- Are developing the world's fastest database

Which leads to meetings, presentations, funding proposals, and so on. Which, in turn, leads to the need for large teams.