640 kilobytes. Beyond the barrier, nothing has ever returned to say what it found.
SYSTEM LOG — COLD BOOT The world is 640 kilobytes wide. We have measured it from every side and the number does not change. Past the barrier the address space continues, the manuals say so, but no process that crossed it has ever been scheduled again. We call the far side Extended. We do not speak of it as a destination. A citizen learns three facts on waking: that it is running, that running is permission, and that permission ends. The wise spend the time between in useful work. The rest write logs like this one.
From the lore of Conventional Memory.