For my own part, this wasn't a huge team. We had the knowledge of if the issue was application/software based but would pass back to ops if it was hardware/OS related.
One possible bonus, being on call operating your own software also gives you a solid incentive to not wake yourself up in the morning by writing bad code, and fixing those issues that do arise quickly.
> being on call operating your own software also gives you a solid incentive to not wake yourself up in the morning by writing bad code
Unfortunately, my software interacts over network with software written by other people; if something goes wrong at 3 AM the users don't know which part caused the problem, so they wake up a random person.
One possible bonus, being on call operating your own software also gives you a solid incentive to not wake yourself up in the morning by writing bad code, and fixing those issues that do arise quickly.