DECWindows: Cannot open display

[Hejib]

When try running xwindows application I get this error. I have tried running decw$examples:ico.exe and that comes up with

Cannot open display
: non-translatable vms error code: 0x1BC
%system-f-nolognam, no logical name match

I have a two node cluster and this works on one and doesn't on another.

I have compared all sys$specific files starting DECW* etc. They all match. Also compared all logicals they all are there.

Can someone please help. Thanks

[Karl Rohwedder]

Graham,

pls. enter a $ SHO DISPLAY?

regards Kalle

[Hejib]

Here is the output

MPDTP1::SYSTEM> show display

Device: WSA14: [super]
Node: 10.48.0.75
Transport: TCPIP
Server: 0
Screen: 0

[Kris Clippeleyr]

Graham,

What kind of system is Node: 10.48.0.75 ?
Does it run some kind of X server?
If so, are the security settings correct?

Just some thoughts.

Kris (aka Qkcl)

[Hejib]

Hi Kris,

Thats my PC. It runs exceed. It works from the 2nd node in the cluster.

[John Gillings]

Graham,

Does SHOW DISPLAY on the working node look the same as on the non-working node? (I assume you've already confirmed that).

I'd also try throwing a display at some other X server to see if the problem might be that particular server. If you've got an OpenVMS X server, maybe try DECnet protocol? Or, if the node has a graphical console try LOCAL to itself.

I'm not familiar with exceed, so don't know what security settings might be needed. Maybe there's a *::* setting to let everything through you could enable for testing?

ICO is an excellent choice of test program. It's simple and has excellent error reporting (at least MOST of the time ;-)

A bigger hammer, (requires CMKRNL) try:

$ SET WATCH/CLASS=MAJ FILE
$ MCR DECW$EXAMPLES:ICO

and compare the sequence of file operations between working and non-working systems. Might give a clue.

Also a big hammer, try comparing the logical names defined on each node (sorry not easy to do). Anything obvious missing from the failing node?

[John Gillings · Accepted solution]

Graham,

A long shot... I found a similar problem report from a long time ago that turned out to be caused by missing "UCX$" logical names. TCPIP services should define both TCPIP$ and equivalent UCX$ logical names. Many things work from the TCPIP$ logical names, so don't care about UCX$. DECwindows uses UCX$ for upwards compatibility.

Is it possible some well meaning person decided to remove all the "superfluous" UCX logical names from one node?

[Hejib]

John,

You know what - you are absolutely briliant. Lucky you had similar problem.
I had tried everything you had suggested. I had also compared logicals on both nodes I found the UCX$INET* logcals missing on the node where DECW is not working. When I ran ico.exe it gave me error of "missing logicals..." or something like that. But since they were UCX$ logicals I thoght why they should be there at all when we have TCP/IP 5.4 exo 5 etc.

As soon as I introduced those logicals (after your suggestion) its all working ok.

Thanks a lot.

[Hejib]

Make sure even when all TCP/IP logcals are defined, DECWindows using TCP/IP transport will require UCX$INET* also defined. They are equivalent of TCPI$INET* logicals.