[Info-vax] SimH with framebuffer and hobbyist kit?

[John E. Malmberg]

On 4/2/2013 4:59 PM, Vertis Sidus wrote:
> On 2013-04-02, Bob Koehler <koehler at eisner.nospam.encompasserve.org> wrote:
>> In article <slrn3vfsklkdre.pc1.vrtsds at sdf.lonestar.org>, Vertis Sidus <vrtsds at sdf.org> writes:
>>> I'd like to use DECwindows in an emulated framebuffer, but the only option I
>>> can find for that is the VAXstation 2000 emulator at
>>>
>>>    http://www.9track.net/simh/vax410
>>>
>>> This is a rather limited system! From what I've read, it really wants VMS
>>> 4.x or so, but unfortunately all I have is the current 7.3 hobbyist kit. Is
>>> it at all possible for VMS 7.3, with DECwindows, to run in this emulator? Or,
>>> is there another framebuffer emulator option that I don't know about?

The author of that variant of SimH has posted on this forum about it, 
and you might contact him to get the source.

>>     I would not be in the least bit surprized if 7.3 ran on a VAXStation
>>     2000 emulator.  I would try it.

<snip>

> Not so lucky in the case of this particular emulator. As
> near as I can tell, the memory won't go above 16MB, and the
> only supported storage is two hard drives (RD31, RD32,
> RD53, or RD54) and a floppy drive. No CD-ROM, of course. I
> don't even get a tape drive.

Even with those limitations, I think I could get VMS 7.3 to run on it as 
a LAVC client.

I used to run a farm of VS2000s for a display only application.  The 
VS2000s network booted VMS.  Oh, and I only had 4 to 6 MB of ram on 
them.  The actual application being displayed on them ran on a VAX 
4000-500.  A fake keyboard plug on them allowed unattended booting.

Way below supported specification, but ran for years.

The problem is that the framebuffer in the emulator is too primitive for 
DecWindows Motif to support.  You need at least 8 bit graphics.

But that still is not good enough.  GTK+ needs at least 24 bit color.
And your performance will be probably slow.

Now some answers to issues raised on your previous posts.

1. A modern Linux running in a VM using paravirtualized I/O drivers has 
negligible overhead.

So it is cheap to create a Linux VM to dedicate to running Simh.  Set up 
for emulated NICs on the VM.  2 for the Linux host, 2 for SimH.
On the host and the emulated system, you have one NIC each for a private 
LAN and one for access to the external network.  Using a VM makes this 
trivial to set up.

You can set up VMs to cause performance loads, but the current Linux 
kernels detect that they are running in an emulator and just turn many 
operations over to the host instead of simulating them like was done in 
ancient times.

2. SimH built with netorking support can handle 512 MB of emulated ram, 
access to a CD-ROM image controlled by the emulator, and emulated disks, 
probably up to a terabyte.  I have only used about 10 GB disks myself.

3. For X11, HP TCP/IP does not support SSH tunneling, so you have to 
lower the security of the X server.  But you only have to do it on your 
private internal network that is local to your system running a VM.  Or 
it may be that of the Process Software TCP/IP products can be used to 
provide SSH tunneling, and they have a hobbyist program.

4. You will need to get VMS specific fonts on the X-Server.  The VAX X11 
software does not have a compatible font server.  The Alpha and IA64 
versions can serve fonts.  So consider an Alpha emulator.  A Windows VM 
will use a bit more resources than Linux.  I have not tried running an 
Alpha emulator on Linux yet.

Regards,
-John
wb8tyw at qsl.network
Personal Opinion Only