[abnercoimbre]

Indeed, arenas are not a new invention, but to quote a knowledgeable friend who's been around longer than us:

> you can find, for example, spolsky writing about [arenas] in 2003

Game engine, embedded, and OS people certainly knew about them. But this is the crucial point:

> it's possible for many people to know/use them, and also for most people not to know/use them

I grew up on Linux forum boards -- with lots of greybeards writing C -- and I was never once exposed to arenas (or bump / linear allocators.)

In school we wrote programs in C, and professors never challenged the forests of mallocs: despite most bugs stemming from them.