Scratch
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#1 2013-03-03 16:16:12
Scratch failing to load on thin clients
Hi,
I'm able to successfully run Scratch 1.4 on my Linux Edubuntu 12.04 server but when I try to load it on a thin client there is only a window filled with white (which unfortunately becomes quite rude when I try to close it). When I load using
scratch -v
I get this output:
==================
$ scratch -v
Executing: /usr/lib/squeak/4.4.7-2357/squeakvm -encoding UTF-8 -vm-display-x11 -xshm -plugins /usr/lib/scratch/plugins/:/usr/lib/squeak/4.4.7-2357/ /usr/share/scratch/Scratch.image /home/naftali/-v
XShmAttach: BadAccess (attempt to access private resource denied)
X Error: BadShmSeg (invalid shared segment parameter)
Major opcode of failed request: 139
Minor opcode of failed request: 3
Serial number of failed request: 84
X Error: BadShmSeg (invalid shared segment parameter)
Major opcode of failed request: 139
Minor opcode of failed request: 3
Serial number of failed request: 86
X Error: BadShmSeg (invalid shared segment parameter)
Major opcode of failed request: 139
Minor opcode of failed request: 3
Serial number of failed request: 87
===================
...which seems to suggest a shared memory problem.
Does anyone have any ideas?
Thanks,
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#4 2013-03-04 17:24:55
Re: Scratch failing to load on thin clients
dbclin wrote:
Thanks, but I'm afraid that won't work in this case - this is a heavily used production environment that can't be changed for just one package.
sorry, I meant other scratch builds...
Think I got it now though, looks like
this bug report could also be useful. Looks to me like you can just remove the -Xshm and then it should connect to the correct X server.
If you don't know much about linux, please run "which scratch" then "cat (whatever path you get from the previous command)" and copy the output to this thread. If you are confident with linux, go ahead and edit the file yourself.
Last edited by TRocket (2013-03-04 17:34:30)
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#5 2013-03-04 18:06:45
Re: Scratch failing to load on thin clients
> Think I got it now though, looks like this bug report could also be useful. Looks to me like you can just remove the -Xshm and then it should connect to the correct X server.
That was bang on...worked a charm!
Now I'm working on getting audio going on the thin client. That was the killer a few years ago when I first tried Scratch. Any ideas?
Thanks a million!
David
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#6 2013-03-04 22:05:25
Re: Scratch failing to load on thin clients
Update: I believe that I will move my problem playing sound in Scratch on a thin client over to Edubuntu forums as the problem seems to be more LTSP-oriented (although if anyone here has any insight, I'd be most appreciative).
In case anyone's interested, here's what I've discovered:
Running scratch -v from a client, I got this after trying to play sound:
sound: /dev/dsp: No such file or directory
on that, http://wiki.debian.org/SoundFAQ reported:
"If the audio mixer application is reporting that no mixer is available, or gives an error:
audio: /dev/dsp: No such file or directory
It is necessary to load the snd-pcm-oss module"
Which suggests that my clients somehow have no access to that module - it must be sucessfully loaded on the system, as Scratch plays sound on my server without trouble.
Thanks TRocket for your help!
David
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#7 2013-03-05 02:14:03
Re: Scratch failing to load on thin clients
You're welcome! I was about to give you https://lists.ubuntu.com/archives/edubu … 03723.html. But I think it's one you filed 
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#8 2013-03-05 12:14:02
Re: Scratch failing to load on thin clients
TRocket wrote:
You're welcome! I was about to give you lists.ubuntu.com/archives/edubuntu-users/2008-March/003723.html. But I think it's one you filed
It was my bug. But at least this time I'm not getting sound output through my server's speakers... 
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#10 2013-03-05 17:42:12
Re: Scratch failing to load on thin clients
TRocket wrote:
For the sound, try also adding -vm-sound-alsa or -vm-sound-oss to the script that calls the squeak vm. (The same line you removed the -xshm from)
Ok. When I tried -vm-sound-alsa I at least managed to get a new error message
soundStart: snd_add_pcm_handler: Function not implemented
which appears to be a known issue. See bugzilla.redhat.com/show_bug.cgi?id=856238 where I found:
"This is a PulseAudio thing -- it's an intentional incompatibility in the ALSA compatibility layer. If you're running PulseAudio, the native support should have been used automatically."
-vm-sound-oss left me where I was before (sound: /dev/dsp: No such file or directory)
Thanks for the ideas,
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