Some long term plans are crazier than others. I would like to have a machine that runs nock directly on the bare metal, but that doesn't mean it fits into the current architecture.
So far to my knowledge everyone running Urbit is doing so on a Unix system of one flavor or another. The point of "they call us, we don't call them" is not that Urbit never calls into Unix, it's that the set of reasons to reach out to Unix for one of the existing OS facilities is limited, restricted from the list growing any longer than absolutely necessary.
If your persisting disk filesystem evaporates from under you in the middle of operation, maybe Urbit can be prepared to deal with this, but as long as you have it there, might as well use it to allow the user to muck around with your internal representations in a way that is already familiar.
One of the problems Urbit doesn't currently seek to tackle is "a new text editor." Surely this is for the best, not because "a new text editor" is not an interesting problem, but for reasons that I think are already obvious to you.
So far to my knowledge everyone running Urbit is doing so on a Unix system of one flavor or another. The point of "they call us, we don't call them" is not that Urbit never calls into Unix, it's that the set of reasons to reach out to Unix for one of the existing OS facilities is limited, restricted from the list growing any longer than absolutely necessary.
If your persisting disk filesystem evaporates from under you in the middle of operation, maybe Urbit can be prepared to deal with this, but as long as you have it there, might as well use it to allow the user to muck around with your internal representations in a way that is already familiar.
One of the problems Urbit doesn't currently seek to tackle is "a new text editor." Surely this is for the best, not because "a new text editor" is not an interesting problem, but for reasons that I think are already obvious to you.