[Info-vax] DZQ11 on VAX/4000 Model 300

[John E. Malmberg]

On 1/15/2019 5:18 PM, David Wade wrote:
> On 15/01/2019 14:33, John E. Malmberg wrote:
>> On 1/15/2019 1:06 AM, Steven Schweda wrote:
>>>> [...] The board I added was a 4-port serial which I
>>>> understood to be low priority. Therefore I placed it at the
>>>> left hand side of the existing cards.
>>>
>>>     A Web search for "The following list shows the recommended
>>> sequence of modules" could be educational on card order.  For
>>> example, page 4-2 of:
>>>
>>> http://bitsavers.trailing-edge.com/pdf/dec/vax/630/
>>> AX-GLBAA-MN_MicroVAX_II_630QB_Technical_Manual_Nov85.pdf
>>>
>>> (My paper copy has the same copyright date, 1985, but a
>>> typewriter-like font.  "AZ-FE09A-TN".)

> Does that apply to the BA400?

The bus layout may be different.  The card order would be the same.

What really matters is if your bus has a "serpentine" in it where you 
have the cards.

A bus with out a serpentine only has 1/2 size cards in the top part and 
not the bottom.

A bus with a serpentine must have two 1/2 size cards together to make a 
full slot.  One of them could be a bus grant card.

And the serpentine may only apply to some of the slots on the bus.

>> All devices greater than BIRQ4 should be closer to the CPU than any 
>> serial card, regardless of what the documentation states or you will 
>> eventually get either a bugcheck or machine check.
>>
>> All Q-bus serial cards that I have seen have a bug in that they only 
>> pass the birq4 related signal from cards after them in the bus.
>>
>> Many 3rd party Q-bus disk controllers are BIRQ5.
>>

>Thats the way the system is built. The Serial card is last on the BUS.

As pointed out in another post, almost all Digital Q-BUS widgets are BIRQ4.

As the BIRQ signals are (supposed) to be looped through each card, in a 
race condition the cards closest to the CPU will get the chance to get 
the BIRQ signal first.

However it should work to have BIRQ5 devices after BIRQ4 devices.  While 
not the best configuration, it is probably rare to stress the system to 
the point it makes a noticeable difference.

>>>     And yes, [SYSGEN or console] CONFIGURE is your friend.
>>> I'd visit it whenever making any change on the Q-bus.
>>
>> A simple running of configure shows that the kzqsa defaults to 
>> floating and shows why the system will not boot.
>>
>> MERCRY> mcr sysgen configure
>> DEVICE> tu81
>> DEVICE> dz11
>> DEVICE> qza
>> DEVICE> ^Z
>> Device: TU81  Name: PTA    CSR: 774500     Vector: 260    Support: yes
>> Device: DZ11  Name: TTA    CSR: 760100*    Vector: 300*   Support: yes
>> Device: QZA   Name: PKA    CSR: 761400*    Vector: 310*   Support: yes
>>
> But the cards go TU811,QZA,DZ11. Does this matter?

No the configure program run from VMS will always report them in that order.

The VAX-4000 model 300 has a configure program in the console rom that 
may behave a little differently.

>> MERCRY> mcr sysgen configure
>> DEVICE> tu81
>> DEVICE> qza
>> DEVICE> ^Z
>> Device: TU81  Name: PTA    CSR: 774500     Vector: 260    Support: yes
>> Device: QZA   Name: PKA    CSR: 761300*    Vector: 300*   Support: yes
>>
>> Adding or removing a serial card or other floating device requires 
>> changing the CSR and vector of the KZQSA.
>>
>> On a VAX-4000 model 300, you do not specify any of the embedded I0 
>> devices when running configure, only what is on the Q-BUS.
>>
> 
> If order matters then the cards go TU81, QZA and DZ11. When I put them 
> into CONFIGURE on the vax I get different answers.

Configure order does not specify bus order.  It just tells you where VMS
and the boot rom expect the settings on the cards to be.

>>>     A "modern" serial card is a CXY08 (M3119):
>>>
>>>        http://antinode.info/dec/cxy08_settings.html
>>
>> Nice, as long as you have the octopus cables for them.
>>
>> For serial, I would look for a used LAT compatible terminal server.
>>
> 
> I was trying to avoid another box.

As long as you keep the baud-rate under about 1200 baud and not 
continuous bursts, the DZ-11 port should work.

The DH / DZ adapters do not have bulkheads that meet the FCC radiation 
suppression requirements in the US for that cabinet.  The CXY08 / CXY16 do.

And those requirements are looser for computer equipment designed for an 
office than in a home.

Not sure what the requirements are for other countries.

You have your answer of why it does not work with out the card.

Which is odd because it should not have worked before you added the 
card, unless you also added the KZQSA.

Regards,
-John