Here was the issue: suddenly the laptop could not connect via wireless. As I didn't have Ethernet wire to test wired connection, so I tried a couple of ways:
1. Restored configuration (no effect)
2. Installed antivirus software Avast (scanned, but not virus found)
3. Checked network adapter device and drivers (good)
4. Safe Mode with network connection (no luck)
I brought the laptop to office and found wired worked. Therefore I believe it is not Virus related, instead of some configuration, so I contacted IT department, and they told me there was a switch for wireless connection. I toggled switch on the left side towards the front by the PCMCIA slots and headphone, then it worked.
Usually for Dell laptop, it is Fn + F2 to switch on/off wireless connection. However, for some models, it is a bit different, need try other Fn combination keys. For Dell Latitude D630, on the left side of the laptop - a real on/off switch for wireless connection. It had been switched off, I turned it back on and found all my wireless networks again.
For more info, read this thread How to turn on/off Wireless in various Laptop Models
Update: 5/18/2012 - Facebook IPO date
I met this issue again, and could not recall this blog. When I try to ipconfig /renew, I got media disconnected error message. After google, I figure out the root cause. My wife switched off the wireless.
Wednesday, January 5, 2011
StackOverflowError
Since JDK1.0, there is such a error (extended from java.lang.VirtualMachineError), thrown when a stack overflow occurs because an application recurses too deeply. This is the java doc from Sun (now part of Oracle). Therefore, usually StackOverflowError results from too deep nest calls, or recursive calls. It might be direct recursive or indirectly recursive.
http://download.oracle.com/javase/1.4.2/docs/api/java/lang/StackOverflowError.html
Recursion is when a function calls itself.
Tail Recursion: A call is tail-recursive if nothing has to be done after the call returns. I.e. when the call returns, the returned value is immediately returned from the calling function. More simply, tail recursion is when the recursive call is the last statement in the function.
Head Recursion: A call is head-recursive when the first statement of the function is the recursive call.
http://www-2.cs.cmu.edu/~cburch/pgss97/slides/0716-recurse.html
Efficiency of Recursion?
Tail Recursion v.s. Iteration?
http://download.oracle.com/javase/1.4.2/docs/api/java/lang/StackOverflowError.html
Recursion is when a function calls itself.
Tail Recursion: A call is tail-recursive if nothing has to be done after the call returns. I.e. when the call returns, the returned value is immediately returned from the calling function. More simply, tail recursion is when the recursive call is the last statement in the function.
Head Recursion: A call is head-recursive when the first statement of the function is the recursive call.
http://www-2.cs.cmu.edu/~cburch/pgss97/slides/0716-recurse.html
Efficiency of Recursion?
Tail Recursion v.s. Iteration?
Tuesday, January 4, 2011
Sound recorder didn't work after WebCam installation
Recently I installed a Logitech WebCam Pro 9000, but my company internal IM didn't work for voice chat. It was the same case for "Sound Recorder" from Windows XP. I can still listen to music, but cannot speak via microphone. After some thoughts, I finally figure out the root cause was WebCam audio becomes the default audio device which takes over my original sound card.
The fix is easy, go to Start -> Settings -> Control Panel -> Sound and Audio Devices, then switch back to original device.
The fix is easy, go to Start -> Settings -> Control Panel -> Sound and Audio Devices, then switch back to original device.
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| Voice Setting |
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| Audio Setting |
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