Yes, you're probably right. It disconnects the console i/o from the process fd's, and so the process sits there blocking - and when you fg, the fd's get re-att

Yes, you're probably right. It disconnects the console i/o from the process fd's, and so the process sits there blocking - and when you fg, the fd's get re-attached and things kick back into place .. while bg'ing the process, I think, re-attaches it to a new thread completely? Ah well, the details are out there somewhere ..