[Simh] More VAX Simulators

[Paul Koning]

> On May 3, 2019, at 3:52 PM, Johnny Billquist <bqt at softjar.se> wrote:
> 
> That came across wrong...
> 
> Flow control would most certainly help, however, when running in a simulator, with a terminal window, connected to the system, there is actually no flow control available, so you will loose data.

Why would there be no flow control available?

Flow control is part of the protocol, no different from escape sequence parsing.  If a terminal emulation receives a control/S from the host, it should stop sending characters to the host.  For that to be meaningful, the "off" action has to happen close enough to where the characters are picked up by the driver that you don't get the simulator equivalent of "Fifo overrun" but that is not hard to arrange.

If the emulation currently doesn't do this, forcing the character rate down to "really slow" should be an adequate workaround.

	paul