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By yianna
Date 2008-02-05 11:06
hi,
i'm trying to display an L2 modis file. In the band list selection window, i select the loaded band and click display. The display window though that opens up, crashes immediately and I get kicked out of seadas. i also see the following message in my terminal:
GENERIC_FILE_TYPE detected a MODIS file.
grp_name=Geophysical Data
Getting - "sst" data from HDF file...
Segmentation fault
I've turn off randomization according to previous posts, and i get:
kernel.randomize_va_space = 0 when i type: /sbin/sysctl -a | grep randomize
But why is my display still crashing?
I'm using seadas 5.1.5 with the embedded idl license on Fedora core 6 system.
Any ideas?
By mike
Date 2008-02-05 16:09
By yianna
Date 2008-02-06 09:29
Hey Mike,
yes, i had resolved the libXp issue. how complex is the issue?
would it be easier to just buy a new mac computer?
-Yianna
By mike
Date 2008-02-06 15:40
Edited 2008-02-06 15:46
First, try rebooting your system and see if the error goes away.
-How much physical RAM does your system have?
-How much swap space does your system have (you can use the "top" Unix command to see this)?
-Is the Level-2 file you're attempting to load a 5-minute granule?
-Does this segfault occur when you try to load other data files?
-When you load the Level-2 file, try increasing the "Pixel Sample Rate" and "Line Sample Rate".. try setting them to a higher value like "8".
-Also try creating a subscene using Process->MODIS->l2_extract and then try loading this subscene.
By yianna
Date 2008-02-08 09:14
Mike,
to answer your questions:
"-How much physical RAM does your system have?"
[yianna@localhost ~]$ free -m
total used free shared buffers cached
Mem: 502 488 13 0 7 263
-/+ buffers/cache: 217 284
Swap: 0 0 0
"-How much swap space does your system have (you can use the "top" Unix command to see this)?"
[yianna@localhost ~]$ top
top - 10:57:53 up 9 min, 1 user, load average: 0.25, 0.42, 0.29
Tasks: 115 total, 1 running, 114 sleeping, 0 stopped, 0 zombie
Cpu(s): 2.7%us, 0.0%sy, 0.0%ni, 97.3%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st
Mem: 514352k total, 507984k used, 6368k free, 6624k buffers
Swap: 0k total, 0k used, 0k free, 304576k cached
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
2514 root 15 0 171m 14m 6616 S 5 2.9 0:11.41 Xorg
3215 yianna 15 0 41264 13m 9392 S 1 2.7 0:00.40 gnome-terminal
3234 yianna 15 0 2164 1008 788 R 0 0.2 0:00.11 top
1 root 15 0 2032 640 548 S 0 0.1 0:00.68 init
2 root RT 0 0 0 0 S 0 0.0 0:00.00 migration/0
3 root 34 19 0 0 0 S 0 0.0 0:00.00 ksoftirqd/0
4 root RT 0 0 0 0 S 0 0.0 0:00.00 watchdog/0
5 root RT 0 0 0 0 S 0 0.0 0:00.00 migration/1
6 root 34 19 0 0 0 S 0 0.0 0:00.00 ksoftirqd/1
7 root RT 0 0 0 0 S 0 0.0 0:00.00 watchdog/1
8 root 10 -5 0 0 0 S 0 0.0 0:00.00 events/0
9 root 10 -5 0 0 0 S 0 0.0 0:00.00 events/1
10 root 15 -5 0 0 0 S 0 0.0 0:00.00 khelper
11 root 10 -5 0 0 0 S 0 0.0 0:00.00 kthread
15 root 10 -5 0 0 0 S 0 0.0 0:00.00 kblockd/0
16 root 18 -5 0 0 0 S 0 0.0 0:00.00 kblockd/1
17 root 18 -5 0 0 0 S 0 0.0 0:00.00 kacpid
"-Is the Level-2 file you're attempting to load a 5-minute granule?"
Yes
"-Does this segfault occur when you try to load other data files?"
Yes. for both L2 and L3 files.
"-When you load the Level-2 file, try increasing the "Pixel Sample Rate" and "Line Sample Rate".. try setting them to a higher value like "8"."
I still get the segmentation fault error.
"-Also try creating a subscene using Process->MODIS->l2_extract and then try loading this subscene."
Still get the error.
By mark
Date 2008-02-08 15:24
Yianna,
It may be that it's crashing because you don't have any swap space set up on your machine. It's easy enough to set up swap space and there are many references on the web for doing this, here's one:
http://www.cyberciti.biz/faq/linux-add-a-swap-file-howto/I would suggest adding at least a gigabyte or two. Let me know how that works out.
Mark
By yianna
Date 2008-02-11 11:15
I created 2 swapfiles, 1GB each.
After rebooting my computer, I see the following with the free -m and more /proc/swaps commands
[yianna@localhost used_by_ucy]$ free -m
total used free shared buffers cached
Mem: 502 360 142 0 4 204
-/+ buffers/cache: 151 350
Swap: 2047 117 1930
[yianna@localhost used_by_ucy]$ more /proc/swaps
Filename Type Size Used Priority
/var/tmp/swapfile1 file 1048568 120780 -1
/var/tmp/swapfile2 file 1048568 0 -2
However, when I try displaying either a L3 or L2 file, I still get the segmentation fault. With the L2 file I still subscene as Mike recommended, and try to display the smaller image, but it display still closes and gives me
Getting - "sst" data from HDF file...
Segmentation fault
Yianna you should find and put old "libX11.so.*" file under the file where you are running seadas and also add a line in your .bashrc.
for bash
export LD_PRELOAD_PATH=/my/private/lib
for tcsh
setenv LD_PRELOAD_PATH /my/private/lib
this my/lib.... has to changed with the path where you put old libX11.so file. For example I am using fedora7 with bash and I put old libX11 file under /home/orek then I add export LD_PRELOAD_PATH=/home/orek line in my .bashrc file.
After modifying .bashrc open new terminal window and run seadas. The trick here is run seadas under the same path, like if you put the libX11 under /home/orek you should run seadas from /home/orek then you may change the working from seadas easily if you like. If you do not have old linX11.so file I can send you via email it is 1 mb file. For editing .bashrc file you may use gedit or other text editors present in Linux..
Cheers
Hasan
ps: you may find some additional info on:
http://www.dfanning.com/misc_tips/segfault.html
By mark
Date 2008-02-11 16:58
Yianna,
I suspect that this may still be an issue related to the problems that IDL 6.3 has with libXp.so.6 on FC6. We have a number of posts concerning this problem on a range of operating system platforms, and it can be very tricky trying to get this to work properly. I would suggest that if you have been through all of the posts and tried everything and it still segfaults on you, perhaps it's time to consider running something else instead of FC6. Either that, or purchase a licensed version of IDL 6.4.
Regards, Mark
By yianna
Date 2008-02-14 10:06
Hi Mark, Mike, Hasan,
I finally purchased IDL7.0 and the seadas display window works fine now. Thanks a lot for your help.
- Yianna
By mike
Date 2008-02-14 17:16
Ok great to hear Yianna!
