[Simh] Multiple telnet ports in SimH to RSTS/E 9.6

[Paul Koning]

> On Dec 31, 2015, at 3:31 PM, Will Senn <will.senn at gmail.com> wrote:
> 
> 
> 
> On 12/31/15 2:26 PM, Paul Koning wrote:
>>> On Dec 31, 2015, at 3:10 PM, Will Senn <will.senn at gmail.com> wrote:
>>> 
>>> ...
>>> Paul Koning set me straight on figuring out that DZ, as configured, was actually working. Duh, press RETURN twice to get BAUD detected properly, then all is right in the world. The other devices might work too, but since DZ worked, I'm happy.
>> In late versions of RSTS/E, the following are supported: DL11 and equivalent, DH11, DZ11 DHV11, DHU11.
>> 
>> DC-11 support existed in RSTS V4A, not sure about later.  I don't remember that DJ11 support was ever done.  Also note that V4A supports only single line interfaces (KL11, DL11, DC11, DL11-E); mux support arrived in RSTS/E V5A.
>> 
>> Originally you specified the terminal configuration with SYSGEN.  As I mentioned, that disappeared at a late stage; I believe in V9.0 but I may be off a bit.  If SYSGEN asks, you need to answer; if a particular version doesn't ask about terminals, that means it has terminal autoconfiguration at boot time.
>> 
>> Something related: RSTS/E knows how to find devices at boot time and disables anything configured that isn't actually present.  That appeared in RSTS V5B.  Before that time, you had to be careful in SYSGEN *not* to specify non-existent devices, because RSTS would try to reference them and crash.
>> 
>> 	paul
>> 
> 
> Is there a noticeable advantage of one over the other in SimH of using DL11, DH11, DZ11, DHV11 or DHU11?

Not likely.  RSTS runs at blinding speed in emulation no matter what you use.  DH/DHV/DHU have DMA output which means fewer interrupts.  On a real PDP11 with very high output demands, that can make a clear difference.  For example, the internal DEC tools used to control systems under test in manufacturing used RSTS, and specifically with DH mux interfaces because of the large output bandwidth required.  But for most applications you're not likely to notice, and that's especially true in emulation.

	paul