[XDM] Can't open display

[JKB]

Hello,

I have posted here few days ago a question about xdm. I have
reinstall DECW$ from scratch on OpenVMS 7.3 (VAX).

On a Unix workstation, I launch
Xephyr -query fermat :1

and this server tries a connection to fermat (VAX) as
SYS$SPECIFIC:[TCPIP$XDM.WORK] contains three new files after each
connection:

$ dir

Directory SYS$SPECIFIC:[TCPIP$XDM.WORK]

HILBERT_1.COM;1 HILBERT_1.ERR;1 HILBERT_1.OUT;1

If I understand, DECW$ tries to start @HILBERT_1.COM;1 and writes
errors in HILBERT_1.ERR;1

$ type HILBERT_1.ERR
[17E 1673458252] xdm error: server open failed for hilbert:1, giving up
$ type HILBERT_1.OUT
$ type HILBERT_1.COM
$ @SYS$COMMON:[SYSEXE]TCPIP$XDM_XSESSION.COM hilbert:1

I have tried to start
$ @SYS$COMMON:[SYSEXE]TCPIP$XDM_XSESSION.COM hilbert:1

and this command returns:
p1 = HILBERT:1
p2 =
Executing SYS$MANAGER:SYLOGIN


Executing run sys$system:decw$wsinit

Can't open display

Executing run sys$system:decw$session

X Toolkit Error: Can't open display: _WSA4:

Fatal error detected, image exiting -- final message:
no safety display could be opened
: non-translatable vms error code: 0xE4A, vms message:
%system-e-unsupported, unsupported operation or function

Connection closed by foreign host.

Why "Can't open display" ?

Help will be welcome,

JKB

[Volker Halle]

JKB,

try opening a display first from your OpenVMS VAX7.3 system to your local X11-Server (Unix Workstation):

$ SET DISPLAY/CREATE/NODE=ip-address-of-workstation/TRANSPORT=TCPIP

Then run the ICO image - it provides good error messages:

$ MC DECW$EXAMPLES:ICO

If that works, initiating the connection via XDM might work as well.

Note that you might need to configure TCPIP transport for DECWindows (see SYS$MANAGER:DECW$PRIVATE_SERVER_SETUP.*).

Volker.

[Volker Halle]

JKB schrieb am Donnerstag, 12. Januar 2023 um 09:34:13 UTC+1:

JKB,

I've just tested this from an OpenVMS VAX V7.3 CHARON system and Xming on my Windows Home PC: it works for me.

Does the X11-Server on your UNIX workstation have something like a log file ? Any messages there ?

Can you trace IP-traffic from the VAX to your Unix workstation ? Any connect to port 6000 ?

VAX$ tcptrace/port=remote=6000 ip-address-of-workstation

Volker.

[JKB]

Post by Volker Halle
JKB,
I've just tested this from an OpenVMS VAX V7.3 CHARON system and Xming on my Windows Home PC: it works for me.
Does the X11-Server on your UNIX workstation have something like a log file ? Any messages there ?

Nothing in log.

Post by Volker Halle
Can you trace IP-traffic from the VAX to your Unix workstation ? Any connect to port 6000 ?
VAX$ tcptrace/port=remote=6000 ip-address-of-workstation

Strange.

$ show display

Device: WSA5: [super]
Node: 192.168.10.20
Transport: TCPIP
Server: 0
Screen: 0

$ mc decw$examples:ico
Cannot open display
: non-translatable vms error code: 0xE4A, vms message:
%system-e-unsupported, unsupported operation or function

On VAX side:

$ tcptrace 192.168.10.20 shows nothing

Same constatation on Unix siide. Of course, I have checked that
tcptrace runs as expected on known traffic:

$ tcptrace 192.168.10.20
ICMP Type = 8 ECHO, Code = 0 , Checksum = ^xE594
ICMP Identifier ^x24C3, Sequence Number = 1 = ^x0001

140AA8C0 53DF0140 004085C5 54000045 0000 ***@.@..S....
63BFDF1E | 0100C324 94E50008 | 6B0AA8C0 0010 ...k....$......c
13121110 00000000 0006914A 00000000 0020 ....J...........
23222120 1F1E1D1C 1B1A1918 17161514 0030 ............ !"#
33323130 2F2E2D2C 2B2A2928 27262524 0040 $%&'()*+,-./0123
37363534 0050 4567
ICMP Type = 0 ECHO_REPLY, Code = 0 , Checksum = ^xED94
ICMP Identifier ^x24C3, Sequence Number = 1 = ^x0001

6B0AA8C0 E79F0140 0040F204 54000045 0000 ***@.@......k
63BFDF1E | 0100C324 94ED0000 | 140AA8C0 0010 ........$......c
13121110 00000000 0006914A 00000000 0020 ....J...........
23222120 1F1E1D1C 1B1A1918 17161514 0030 ............ !"#
33323130 2F2E2D2C 2B2A2928 27262524 0040 $%&'()*+,-./0123
37363534 0050 4567

Regards,

JKB

[Volker Halle]

Post by JKB
$ tcptrace 192.168.10.20 shows nothing

JKB,

that indicates, that the error message is being generated by the OpenVMS VAX system itself and ICO does not even attempt to connect to your X11-server on the Unix workstation. You had the TPCTRACE command executing on a second terminal session on your VAX, while you issued the $ MCR DECW$EXAMPLES:ICO command - right ?

There is one other mention of this error message in comp.os.vms from 1996, but no solution...

Volker.

[JKB]

Post by Volker Halle

Post by JKB
$ tcptrace 192.168.10.20 shows nothing

JKB,
that indicates, that the error message is being generated by the OpenVMS VAX system itself and ICO does not even attempt to connect to your X11-server on the Unix workstation. You had the TPCTRACE command executing on a second terminal session on your VAX, while you issued the $ MCR DECW$EXAMPLES:ICO command - right ?

Yes.

Post by Volker Halle
There is one other mention of this error message in comp.os.vms from 1996, but no solution...

To be sure, I have reinstalled DECW$ (DECW$TAYLOR) with all
packages. Same result.

JKB

[Volker Halle]

Post by JKB
To be sure, I have reinstalled DECW$ (DECW$TAYLOR) with all
packages. Same result.

JKB,

everything o.k. with licenses ?

I'm not sure, that DECW$TAYLOR is the correct tool to install/configure DECwindows-MOTIF under OpenVMS VAX V7.3. On my V7.3 system, PROD SHO HIST lists

CHARON $ prod sho hist
----------------------------------- ----------- ----------- --------------------
PRODUCT KIT TYPE OPERATION DATE AND TIME
----------------------------------- ----------- ----------- --------------------
...
DEC VAXVMS DWMOTIF V1.2-4 Full LP Install 14-MAR-2008 12:54:58
...

There is DECW$EXAMPLES:ICO.C, but I'm not sure, if you could complie/link that with the debugger.

One could patch the image header of ICO.EXE to allow it to be run with the debugger, but then you might end up at the XOpenDisplay call, which will most likely return an error - and then what ? Those sources are not even on the (V6.1) source listing CDs.

Volker.

[JKB]

Post by Volker Halle

Post by JKB
To be sure, I have reinstalled DECW$ (DECW$TAYLOR) with all
packages. Same result.

JKB,
everything o.k. with licenses ?

I think.

Post by Volker Halle
I'm not sure, that DECW$TAYLOR is the correct tool to install/configure DECwindows-MOTIF under OpenVMS VAX V7.3. On my V7.3 system, PROD SHO HIST lists
CHARON $ prod sho hist
----------------------------------- ----------- ----------- --------------------
PRODUCT KIT TYPE OPERATION DATE AND TIME
----------------------------------- ----------- ----------- --------------------
...
DEC VAXVMS DWMOTIF V1.2-4 Full LP Install 14-MAR-2008 12:54:58
...

$ prod show prod *
----------------------------------- ----------- ------------
PRODUCT KIT TYPE STATE
----------------------------------- ----------- ------------
DEC VAXVMS DWMOTIF V1.2-6 Full LP Installed
DEC VAXVMS FORTRAN V6.6-201 Full LP Installed
DEC VAXVMS TCPIP V5.3-18 Full LP Installed
DEC VAXVMS VMS V7.3 Transition Installed
HP VMS LD V8.3 Full LP Installed
----------------------------------- ----------- ------------

5 items found

Post by Volker Halle
There is DECW$EXAMPLES:ICO.C, but I'm not sure, if you could complie/link that with the debugger.
One could patch the image header of ICO.EXE to allow it to be run with the debugger, but then you might end up at the XOpenDisplay call, which will most likely return an error - and then what ? Those sources are not even on the (V6.1) source listing CDs.

I will try to build ico.exe.

Best regards,

JKB

[chris]

Post by JKB
Hello,
I have posted here few days ago a question about xdm. I have
reinstall DECW$ from scratch on OpenVMS 7.3 (VAX).
On a Unix workstation, I launch
Xephyr -query fermat :1
and this server tries a connection to fermat (VAX) as
SYS$SPECIFIC:[TCPIP$XDM.WORK] contains three new files after each
$ dir
Directory SYS$SPECIFIC:[TCPIP$XDM.WORK]
HILBERT_1.COM;1 HILBERT_1.ERR;1 HILBERT_1.OUT;1
errors in HILBERT_1.ERR;1
$ type HILBERT_1.ERR
[17E 1673458252] xdm error: server open failed for hilbert:1, giving up
$ type HILBERT_1.OUT
$ type HILBERT_1.COM
I have tried to start
p1 = HILBERT:1
p2 =
Executing SYS$MANAGER:SYLOGIN
Executing run sys$system:decw$wsinit
Can't open display
Executing run sys$system:decw$session
no safety display could be opened
%system-e-unsupported, unsupported operation or function
Connection closed by foreign host.
Why "Can't open display" ?
Help will be welcome,
JKB

The message is clear. On unix at least, that usually means that the X
server can't find a valid display device hw to connect to. The
xorg.conf file defines the screen and display device, right
down to the hardware pci bus node id. The device bus is often probed
and autoconfigured at os install, so you get a desktop login at
reboot, on modern systems. Won't work without a valid display
adapter and the correct device driver installed and loaded. All that
needs to be verified.

Manually, you would call X to autoconfigure, with the command line
X --configure. That would generate a file named xorg.conf.new, which
would then copy to /etc/X11/xorg.conf, or similar. For all X errors,
there should be an X log file called Xorg.0.log, for a single display.
Note that X won't work without a running network, as it needs the
loopback device for the underlying xdmcp protocol...

On VMS, all that may be hidden under the hood, but it must be there
in some form or another...

Chris

[Matthew R. Wilson]

Post by JKB
Hello,
I have posted here few days ago a question about xdm. I have
reinstall DECW$ from scratch on OpenVMS 7.3 (VAX).
On a Unix workstation, I launch
Xephyr -query fermat :1

Don't take this as definitive... but I remember seeing in the past that
the XDM on OpenVMS 7.3 has trouble with anything but display 0. Since
you're running Xephy as display 1, I don't know that it will ever work.

Additionally, if you're using Xephyr, you're probably using too new a
version of X on the Linux/Unix side. To get anything working with X on
my VMS 7.3 system, I needed to install backrev versions of Linux distros
in a VM to get an old enough version of X11 that worked with the old VMS
version. Maybe start by trying something of the RHEL 6 or 7 era (which
I think would have Xnest, not Xephyr).

-Matthew