[Simh] VAX DZ terminal controller unit?

[Gary Lee Phillips]

On Fri, May 20, 2011 at 12:43 PM, Bucher, Andreas (Andreas)** CTR **
<andreas.bucher at alcatel-lucent.com> wrote:

> Nevertheless, this is a crude workaround only, there should be either some settings in VMS to change that behaviour, or something in SIMH is not behaving correctly, hiding the disconnected state of the terminal and making VMS thing that nothing changed.
>

I did discover this approach last night. It's crude, but it works. I
agree that the problem could be VMS itself, or maybe the hardware
being emulated really misbehaved this way (though I doubt that.) I
think it more likely to be an oversight (bug) in the design of the DZ
interface emulation. The original hardware connected to serial lines,
and no doubt understood DTR, RTS, DSR, etc. So if you really
disconnected your terminal, by dropping the DTR, the interface should
have cleared immediately. Since the emulation is using a TCP link, it
may not translate the disconnect into a signal that the VMS system
recognizes as a disconnect, hence we get the timeout period instead.

Thanks for going to the trouble of confirming the behavior, though. At
least that lets me know it isn't peculiar just to my setup, and that's
useful information.

--Gary