Screen won't refresh until PC Reboots

[jeffw_00]

Hi - I run UltraVNC on an updated, clean, Win XP SP3 system, to VNC into a Centos 5.6 system. Sometimes, I open a session and the screen is black. I wave the cursor across the screen and various pixels in its path refresh, but that's it. I try "request screen refresh" and it doesn't help. I exit and restart VNC on the PC, and it doesn't help. I try killing the VNC sessions and starting new ones, it doesn't help. I REBOOT the PC and that fixes it. But that's a pain. Is there a better fix? Thanks!
/j

[B]

I'm beginning to think there's some kind of local caching problem with the new viewer.

I would try the following:

1. Older version of the VNC viewer (can extract out of, for example, the 1.0.8.2 zip file).

2. TightVNC.

3. SSVNC.

[jeffw_00]

I'd like to stick to UltraVNC because I use the FTP feature - I can try an older version though
thanks
/j

[jeffw_00]

whoops -was about to re-install and re-read your response - how do I access the zip file you mention?

[B]

Try one of the "binary zips" at http://www.uvnc.com/downloads/ultravnc/ ... 10961.html

But beware that file transfer does NOT usually work across different version numbers.

[jeffw_00]

oh, then I guess I need to re-install completely at both ends.

just as well, the only zips at that link are 10961.

thanks
/j

[B]

No, no.

I was talking about taking one of those zips and extracting ONLY the vncviewer.exe file. It works standalone.

And zips for the OTHER releases are available from the uvnc.com download section as well. That was just an example (though a bad one in your case; I should have linked the 1.0.8.2 section.)

[jeffw_00]

understood.

but I forgot to mention. I -also- use it to VNC between 2 XP machines, (hence the need for FTP), so I need to update (well, downdate) both installs.
thanks!
/j

[jeffw_00]

Hi - I'm sorry to sat that the older version 1.0.8.2 has reduced, but not eliminated the problem. I reboot daily, but every 3-4 days I need an additional mid-day reboot because UltraVNC has stopped refreshing the screen. Closing/restarting the viewer doesn't help, neither does "Request Screen Refresh". Is there anything to be done about this?

Thanks!
/j

note that in this new incarnation - the failure mechanism is as follows:

1) work happily in VNC
2) change context to a different application - window obscures part of VNC window
3) go back to VNC, obscured part of window is black and stays black - waving the cursor over it "unerases" it, one character-sized block at a time.

[B]

Hmm, if you're still talking about a CentOS target server, then I wonder what happens when you try a different VNC viewer (Tight, Tiger, Real, etc.). At worst case you could schedule the VNC server service or daemon (on Windows or Linux, respectively) to be restarted on a regular basis. Klunky, but mostly effective.

[jeffw_00]

HI - I can switch to TightVNC and see if it recurs. I'm rebooting the machine running the -Viewer- to fix it, so I'm not sure how restarting the Server will make a difference.

Thanks
/j

[B]

Oh... then it wouldn't!

(Probably.)

I really don't know if UltraVNC viewer keeps a cached version of previous connection screens between sessions -- my assumption was that it did NOT. In other words, completely closing the viewer should be returning you to a blank slate. I guess I still wonder if some kind of caching is going on at the server end. What VNC server is running on the CentOS box?

[jeffw_00]

It's the native vnc that comes with the centos release. I'll try switching to TightVNC for a few days and see if the problem recurs.

I see your point though, it seems odd that I terminate the viewer. Restart the viewer, and the screen is still corrupted, but if I terminate the viewer, restart the (viewer) PC, and then start the viewer all is well. From the server point of view, it should be unaware of the intervening reboot on the viewer end.

I AM also running the UVNC server on the PC. It's not active when I'm running the viewer, but it's there. Perhaps somehow the viewer state isn't being cleared when the viewer is terminated because the server process is maintaining viewer state?

(Sometimes I'm at work VNCed to Linux, Sometimes I'm at home VNCed to the PC, never both).

thanks!
/j

[B]

Nah, I'd bet a small amount of money that the UltraVNC server has nothing to do with it. It could even be something weird like your video RAM. Maybe try changing resolutions between VNC viewer restarts?

[jeffw_00]

i can try that 8-}
/j

[jeffw_00]

changing resolution to something else and back fixed it. Thanks. Does this tell me anything that could help eliminate the problem?

[B]

Hmm, seems as if I may have won that small amount of money.

Sure -- try installing an update to your video driver, if one is available. If not, you can try working in a different resolution full-time and see if that helps. Finally, you could always switch to a different video card entirely.

Since this doesn't really seem to have anything to do with VNC per se, I don't know that any VNCViewer changes or bugs apply. (Still, you could experiment with the mirror driver, alpha blending on the server, etc.)

If it were me and nothing else worked, I might write a small batch file to automatically switch video modes on demand. There are lots of system tray tools that will do that too.