# problems running Psychtoolbox

**URL:** <https://psychtoolbox.discourse.group/t/problems-running-psychtoolbox/753>\
**Category:** Uncategorized\
**Created:** [August 29, 2007, 12:47am UTC](https://psychtoolbox.discourse.group/t/problems-running-psychtoolbox/753 "2007-08-29T00:47:28Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![Allen\_Ingling](https://avatars.discourse-cdn.com/v4/letter/a/a183cd/32.png) [@Allen\_Ingling](https://psychtoolbox.discourse.group/u/Allen_Ingling)\
**Post date:** [August 29, 2007, 12:47am UTC](https://psychtoolbox.discourse.group/t/problems-running-psychtoolbox/753/1 "2007-08-29T00:47:28Z")

</div>

Hello everyone,  
  
I have installed the latest Psychtoolbox version and tried to use it.  
However, I couldnt run even a basic script. Here is what I tried to run:  
  
w=screen(0,'openwindow',127);  
hidecursor;  
screensize=screen(w,'rect');  
YY\_2=round(screensize(4)/2);  
screen(w, 'textfont', 'Arial');  
screen(w, 'textsize', 100);  
screen(w, 'drawtext', 'PRESS SPACE TO TEST', 280, YY\_2-100, 255);  
testkey=kbname('space');  
[t, K]=waitforkey;  
if K(testkey)  
 screen(w, 'close');  
 showcursor;  
end  
  
When I run it, it first goes to white screen (while testing and  
calibrating hardware I assume), then it display the gray screen and it  
exits when I press spacebar. It doesnt show any text on the screen.  
Sometimes, it may show it very briefly right after I press spacebar  
and before it exits, but not even every time. What is going on?  
I am running Matlab 7.4.0.287 (R2007a) in Windows XP SP2. Here are  
some messages it outputs in Matlab prompt:  
  

> \>\> ax\_temp

PTB-INFO: This is the OpenGL-Psychtoolbox version 3.0.8. Type  
'PsychtoolboxVersion' for more detailed version information.  
PTB-INFO: Psychtoolbox is licensed to you under terms of the GNU  
General Public License (GPL). See file 'License.txt' in the  
PTB-INFO: Psychtoolbox root folder for a copy of the GPL license.  
  
OpenGL-Extensions are: GL\_ARB\_multitexture GL\_EXT\_texture\_env\_add  
GL\_EXT\_compiled\_vertex\_array GL\_S3\_s3tc GL\_ARB\_depth\_texture  
GL\_ARB\_fragment\_program GL\_ARB\_fragment\_program\_shadow  
GL\_ARB\_fragment\_shader GL\_ARB\_multisample GL\_ARB\_occlusion\_query  
GL\_ARB\_point\_parameters GL\_ARB\_point\_sprite GL\_ARB\_shader\_objects  
GL\_ARB\_shading\_language\_100 GL\_ARB\_shadow GL\_ARB\_shadow\_ambient  
GL\_ARB\_texture\_border\_clamp GL\_ARB\_texture\_compression  
GL\_ARB\_texture\_cube\_map GL\_ARB\_texture\_env\_add  
GL\_ARB\_texture\_env\_combine GL\_ARB\_texture\_env\_crossbar  
GL\_ARB\_texture\_env\_dot3 GL\_ARB\_texture\_mirrored\_repeat  
GL\_ARB\_transpose\_matrix GL\_ARB\_vertex\_blend  
GL\_ARB\_vertex\_buffer\_object GL\_ARB\_vertex\_program GL\_ARB\_vertex\_shader  
GL\_ARB\_window\_pos GL\_ARB\_draw\_buffers GL\_ATI\_draw\_buffers  
GL\_ATI\_element\_array GL\_ATI\_envmap\_bumpmap GL\_ATI\_fragment\_shader  
GL\_ATI\_map\_object\_buffer GL\_ATI\_separate\_stencil  
GL\_ATI\_shader\_texture\_lod GL\_ATI\_texture\_compression\_3dc  
GL\_ATI\_texture\_env\_combine3 GL\_ATI\_texture\_float  
GL\_ATI\_texture\_mirror\_once GL\_ATI\_vertex\_array\_object  
GL\_ATI\_vertex\_attrib\_array\_object GL\_ATI\_vertex\_streams  
GL\_ATIX\_texture\_env\_combine3 GL\_ATIX\_texture\_env\_route  
GL\_ATIX\_vertex\_shader\_output\_point\_size GL\_EXT\_abgr GL\_EXT\_bgra  
GL\_EXT\_blend\_color GL\_EXT\_blend\_func\_separate GL\_EXT\_blend\_minmax  
GL\_EXT\_blend\_subtract GL\_EXT\_clip\_volume\_hint  
GL\_EXT\_draw\_range\_elements GL\_EXT\_fog\_coord GL\_EXT\_framebuffer\_object  
GL\_EXT\_multi\_draw\_arrays GL\_EXT\_packed\_pixels GL\_EXT\_point\_parameters  
GL\_EXT\_rescale\_normal GL\_EXT\_secondary\_color  
GL\_EXT\_separate\_specular\_color GL\_EXT\_shadow\_funcs GL\_EXT\_stencil\_wrap  
GL\_EXT\_texgen\_reflection GL\_EXT\_texture3D  
GL\_EXT\_texture\_compression\_s3tc GL\_EXT\_texture\_cube\_map  
GL\_EXT\_texture\_edge\_clamp GL\_EXT\_texture\_env\_combine  
GL\_EXT\_texture\_env\_dot3 GL\_EXT\_texture\_filter\_anisotropic  
GL\_EXT\_texture\_lod\_bias GL\_EXT\_texture\_mirror\_clamp  
GL\_EXT\_texture\_object GL\_EXT\_texture\_rectangle GL\_EXT\_vertex\_array  
GL\_EXT\_vertex\_shader GL\_HP\_occlusion\_test GL\_NV\_blend\_square  
GL\_NV\_occlusion\_query GL\_NV\_texgen\_reflection GL\_SGI\_color\_matrix  
GL\_SGIS\_generate\_mipmap GL\_SGIS\_multitexture  
GL\_SGIS\_texture\_border\_clamp GL\_SGIS\_texture\_edge\_clamp  
GL\_SGIS\_texture\_lod GL\_SUN\_multi\_draw\_arrays GL\_WIN\_swap\_hint  
WGL\_EXT\_extensions\_string WGL\_EXT\_swap\_control   
  
PTB-INFO: OpenGL-Renderer is ATI Technologies Inc. :: 128MB ATI Radeon  
X1300 x86/SSE2 :: 2.0.5885 WinXP Release  
PTB-Info: VBL startline = 1050 , VBL Endline = 1078  
PTB-Info: Measured monitor refresh interval from beamposition =  
16.698684 ms [59.884960 Hz].  
PTB-Info: Will use beamposition query for accurate Flip time stamping.  
PTB-Info: Measured monitor refresh interval from VBLsync = 16.702540  
ms [59.871132 Hz]. (291 valid samples taken, stddev=0.298258 ms.)  
PTB-Info: Reported monitor refresh interval from operating system =  
16.666667 ms [60.000000 Hz].  
PTB-Info: Small deviations between reported values are normal and no  
reason to worry.  
PTB-INFO: Using OpenGL GL\_TEXTURE\_RECTANGLE\_EXT extension for  
efficient high-performance texture mapping...  
  
PTB-ERROR: Screen('Flip'); timestamping computed an \*impossible value\*  
418739.604343, which would indicate that  
PTB-ERROR: stimulus onset happened \*before\* it was actually requested!  
(Earliest possible 418739.605307).  
PTB-ERROR: Something is broken in your systems timestamping.  
High-precision timestamping disabled,  
PTB-ERROR: reported timestamps will be less robust and accurate, but  
hopefully at least not completely wrong.  
PTB-ERROR: Please try to find and fix the problem if you rely on exact  
stimulus timing.  
  
Thank you.