"sokolov@alpha.CES.CWRU.Edu" "Michael Sokolov" wrote:

>   Wait a minute! These -A and -B things are related to DEC OS licensing
> (single-user vs. multiuser or something like that), right? So one can
> actually change the licensing status with a simple jumper? Cool. I have
> thought that DEC would make a special 200-pin surface-mounted ASIC just for
> this purpose, unmarked like a military helicopter, to make sure that people
> don't even dare to touch this thing. Hey, I'm impressed! Can you also do
> that with MicroVAX vs. VAXserver distinctions on KA650/655 and KA41?

For the MicroVAX 2000/VAXstation 2000, the console needs to know whether to 
write to the serial port or to the video before it does anything else. So 
displaying KA410-A on serial and KA410-B on video is fairly easy. As for 
licensing schemes, Digital has never concentrated on incorporating heavy-duty 
licencing. The KA650-A and KA650-B differ only in the EPROM, and that difference 
is probably only one bit in the second longword so that the OS can determine 
which board it is running on, assuming it cares. The same is true for the 
KA41-A/KA41-B and KA41-D/KA41-E.

>   But what about "F..." vs. "F_..."? Does the system ROM lie that the mono
> video doesn't exist when it's not used for the console? Is this based on
> the licensing jumper setting or on the console selection? Or maybe DEC did

I'm guessing that the console doesn't initialise the video, so there is not much 
point telling you it is there. The jumper is not there for licencing purposes. 
It is there so the console knows whether it is supposed to behave as a 
workstation or as a microvax; the fact that the OS gets to know is incidental.

>   Your textual picture of the MV3100 back panel indicate some switch where
>VS3100 has the console switch. Is the switch on MV3100 also for the
>console? Does this mean you can convert MV3100 to VS3100? Does this mean
>that KA41 has mono video capabilities? But even if it does, how can you
>access them? According to your picture, it doesn't have a video DB15. Or
>maybe some of the numerous otherwise unused pins on the DB25 are used for
>this purpose?

There is a switch on the MicroVAX 3100s that activates what is called the 
alternate console. This moves the console from the normal MMJ to the printer 
port (I think) and also allows the machine to be halted by sending a break on 
the console line (same as the MicroVAX II/III series). If you activate the 
alternate console, by setting the switch up, you still have a MicroVAX 3100 but 
now you can halt it from the console terminal without having to walk up to the 
box and press the halt button.

The MicroVAX 3100s (KA41 series) do not have video circuitry so there is no 
question of converting a KA41 to a KA42 or vice-versa. What you can do is set 
the corresponding switch up (I think) on the VAXstation 3100 and then it will 
use the printer port MMJ (I think) as an alternate console. So you can run your 
VAXstation 3100 as though it were a MicroVAX. OpenVMS treats is as a VAXserver 
3100; however I believe that the box which was actually sold as a VAXserver 3100 
(many years ago) was a KA41-B and not a KA42-A.


>   MV3100 M30+ is a completely different beast. The lack of support for it
>in ULTRIX and NetBSD is one of the consequences of this. BTW, this family
>includes some VAXstations (VS4000) as well as MicroVAXen. Are the system
>boards the same in these MicroVAXen and VAXstations? I think that VS4000s
>always have video on an add-on daughterboard, so the system board should be
>the same.

The MicroVAX 3100-30 is based on the SOC chip (the 3100-40 is the same board but 
in a bigger box). The only other systems that I think are based on the SOC chip 
are the VAXstation 4000VLC and the VAX 4000-200. The latter is obviously 
different (Q-bus!) but I don't have a VLC to hand so I cannot state for sure 
that it is not based on the 3100-30 board. (Actually, the DECnis 500/600 are 
also based on the SOC chip, but those are definitely different boards and no 
NetBSD support is planned ...). Further up the series, the MicroVAX 3100-80 and 
VAXstation 4000-60 are both based on the Mariah chipset (as used in the VAX 
6000-500 series) but the boards are completely different (they are even a 
different size!). The MicroVAX 3100-9x are all based on variations on the NVAX 
chip as are the VAXstation 4000-9x; but since I have none of the VAXstations 
4000-90 I cannot comment much. However, last time I looked they all had 
different 54-xxxxx-xx part numbers, so I presume they are all different boards.

Antonio

Antonio Carlini                            Mail: carlini@marvin.enet.dec.com
DECnet-Plus for OpenVMS Engineering
Digital Equipment Corporation              Worton Grange, Reading, England