Search engines also frequently make web pages they have indexed available from their cache.
A TTL value of 86400 would mean that, if a DNS record was changed on the authoritative nameserver, DNS servers around the world could still be showing the old value from their cache for up to 24 hours after the last update by client.
What he referred to was their cache of gunpowder.
When the other units are notified of the updated cache, they will turn off the valid bit for their cache of that variable.
In a first step, the birds protected their cache when dominants were visible but not when they could only be heard from an adjacent room.
With the peephole open, the ravens guarded their caches against discovery when they could hear dominants in the adjacent room, even when the dominant's sounds were playbacks of recordings.