The sad thing is that this was all already implemented and done in Microsoft's second POSIX subsystem for Windows NT. It provided signals and process groups support for job control shells. It had a full control sequence interpreter for output and control sequence generator for extended keys. There were termcap/terminfo database records that people had added to other operating systems. It had a line discipline with "canonical" and "raw" modes. It had pseudo-terminals, with both BSD and System 5 access semantics.

* https://technet.microsoft.com/en-gb/library/bb497016.aspx

* https://technet.microsoft.com/en-gb/library/bb463219.aspx

* https://news.ycombinator.com/item?id=12866843

* http://jdebp.info./FGA/interix-terminal-type.html

And Microsoft owns it.

I mean, the same is true on Unix. If an app is in the background and wants to write to (or read from) the terminal, it gets SIGTTOU (SIGTTIN) sent to it immediately. It might have to be impossible on Windows to ignore SIGTTOU/SIGTTIN/SIGTSTOP, but I think that's just fine.

Mind you, ptys + tmux/similar is certainly very good, and if that's all we'll get that's still way way better than the current state of affairs, but if that's all that will be possible it should at least be possible to pause the console's output (and flow-control the console application).