[Simh] DZ11 vs DZV/DZQ11

[Johnny Billquist]

On 2018-04-09 22:16, Mark Pizzolato wrote:
> On Monday, April 9, 2018 at 11:57 AM, Johnny Billquist wrote:
>> I think the whole concept of deriving the number of controllers based on units
>> in simh is wrong.
>> I think one should configure each controller separately, including being able to
>> tell what CSR and vector it has, and how many units should be connected one
>> way or another, and any other relevant information.
> 
> Well, that was not how these things were written long ago.   What you're
> suggesting would require a rather dramatic rewrite of essentially all of the
> Unibus and Qbus devices.  If you've got the time, please go head.  :-)

I know. I still consider it a design flaw. And no, I do not have the 
time. :-)

>> For serial ports, that
>> obviously means that you might connect one line to a physical line, another to
>> a telnet listener, and another one not connected to anything at all.
> 
> You can actually do that right now.  Each line on any multiplexer device can
> have a separate TCP listener or be connected to a remote TCP port or to a
> local serial port, or be part of the pool of ports which may optionally be
> configured to listen for the mux device.

Right. But I cannot skip a few lines. And simh really dislikes me if the 
number is not a multiple of 8.

>> And exactly
>> how many units/lines the controller have should also be a factor here then.
>>
>> This also comes back to disks, where I might not want to configure four disks
>> on one controller, but maybe one controller per disk.
> 
> The device simulation for DEC's disk controllers usually default to the
> maximum number of disk devices each controller was capable of supporting.
> Each of those device units can be disabled so if you want one controller per
> disk, you absolutely can.
> 
> Up to 4 separate MSCP controllers can be configured today (with up to 16
> separate drives).  A single RP controller with up to 8 drives is available.
> 
> This functionality has solved most user problems without issue.  If you've
> got a simulation need for more than this, you can extend or rewrite what's
> there now.  Since configurations that can be simulated today can far exceed
> what was ever possible on any real system, it seems like a lot of work to
> address the theoretical flexibility you're asking for.  :-)

I'd like to have more than 4 disks on one MSCP controller. There is 
absolutely no reason for the limit of 4. That's just an implementation 
detail on some of the existing MSCP controllers, but there are MSCP 
controllers who also take more than 4 disks.
And that exists in real life, and I cannot do that (and a bunch of other 
setups) in simh, so I'd say that simh is rather more limited than real 
life. :-)

Same story for TMSCP.

   Johnny

> 
> - Mark
> 


-- 
Johnny Billquist                  || "I'm on a bus
                                   ||  on a psychedelic trip
email: bqt at softjar.se             ||  Reading murder books
pdp is alive!                     ||  tryin' to stay hip" - B. Idol