Seems to me they skipped right over the most obvious option: Redis.
It's quite fast, you can use a Redis string as a random-access array up to 512MB/each, and there are several good ways to handle persistence/backup. I don't think there was a need for them to write any C themselves.
It's quite fast, you can use a Redis string as a random-access array up to 512MB/each, and there are several good ways to handle persistence/backup. I don't think there was a need for them to write any C themselves.