> You could but you'd have no system calls available. True, but to be fair though, games developers had little (if any) need for system calls into the kernel,

> You could but you'd have no system calls available. True, but to be fair though, games developers had little (if any) need for system calls into the kernel, and we'd often make use of that RAM. Not that I recall exactly what we were using it for, it varied game to game — disclaimer: several published C64 games, but I've not messed with any of this since the early 90s!