I want to know what technology google uses for scheduling and sending notifications of Google calendar event.
For scheduling, we usually use Quartz, Spring scheduler etc. These systems are good at their work. But if we want to send a notification only at specified time like "Google calendar event notification before 10 mins", what technology should be used.
Since it is such an important event, the system used should be fault-tolerant, accurate(since notification after 5 mins is not a valid one), scalable(eg. google calendar is used world wide).
Keeping such requirement in mind, what should be the technology/architecture used for designing such application. Thanks in advance!