Analog clock. How many times does the hour and minute hands overlap?

October 20, 2007 | Leave a Comment

Imagine an analog clock set to 12 o’clock. Note that the hour and minute hands overlap. How many times each day do both the hour and minute hands overlap? How would you determine the exact times of the day that this occurs?

Posted by | Filed Under Algorithms 

An analog clock reads 3:15.

October 20, 2007 | 1 Comment

What is the angle between the minute hand and hour hand?

Posted by | Filed Under Algorithms 

How to delete Web Service Extensions

October 4, 2007 | Leave a Comment

There are a few of ways to work-around this:

  1. Manually edit metabase.xml to remove the Web Service Extension
  2. Manually edit metabase.xml to change the Web Service Extension to be deletable, then run iisext.vbs to delete it
  3. Change iisext.vbs to delete “read-only” Web Service Extensions

Whichever option you choose depends on what you are comfortable with. I personally prefer #3 because it is the least invasive, and I do not encourage manual editing of metabase.xml. XML is finicky in format so more things can go wrong than right.

Modification of metabase.xml by Removal

  1. NET STOP IISADMIN /Y
  2. Open %windir%\System32\inetsrv\metabase.xml with an editor like notepad (if on 64bit machine, make sure to do this with a 64bit editor because 32bit editor will be restricted from accessing the System32 directory under which metabase.xml resides) 
  3. Search for the word “WebSvcExtRestrictionList” (sans the quotes)
  4. Look through the list of items and locate the Web Service Extension you want to delete and remove that entire line. Be careful if it happens to be the first or last item on the list - you must preserve the leading/trailing quotes of the WebSvcExtRestrictionList attribute
  5. NET START W3SVC (and restart any other services that stopped with NET STOP IISADMIN /Y)

    Yes, I know there is Edit While Running that simplifies the first and last steps, but I do not like turning on more product features to perform product work-arounds. Remember you are trying to work-around something, so you want less, not more code of that “something” (in this case IIS) running. You can make your own judgement.

Modification of metabase.xml by Changing

  1. NET STOP IISADMIN /Y
  2. Open %windir%\System32\inetsrv\metabase.xml with an editor like notepad (if on 64bit machine, make sure to do this with a 64bit editor because 32bit editor will be restricted from accessing the System32 directory under which metabase.xml resides)
  3. Search for the word “WebSvcExtRestrictionList” (sans the quotes)
  4. Look through the list of items and locate the Web Service Extension you want to delete and change its “0″ to a “1″. For example, suppose I want to change ASP to be deletable. I would change the following: 
    1,C:WINDOWSSystem32inetsrvasp.dll,0,ASP,Active Server Pages

    to: 

    1,C:WINDOWSSystem32inetsrvasp.dll,1,ASP,Active Server Pages
  5. NET START W3SVC (and restart any other services that stopped with NET STOP IISADMIN /Y)

    Yes, I know there is Edit While Running that simplifies the first and last steps, but I do not like turning on more product features to perform product work-arounds. Remember you are trying to work-around something, so you want less, not more code of that “something” (in this case IIS) running. You can make your own judgement.

  6. Now run your iisext.vbs /RmFile command and it should succeed.

Modification of iisext.vbs

  1. You should search for the following block of code in %windir%\System32\iisext.vbs: 
    For i=0 to UBOUND(restrictions)
    If UCASE(restrictions(i).FilePath) = UCASE(strAppName) Then
        If restrictions(i).Deletable = 1 Then
            WebSvcObj.DeleteExtensionFileRecord strAppName
            bDel = True
        End If
    End If
Next
  2. And change it to this (note the single-quote added at the beginning of those two lines): 
    For i=0 to UBOUND(restrictions)
    If UCASE(restrictions(i).FilePath) = UCASE(strAppName) Then
        ‘If restrictions(i).Deletable = 1 Then
            WebSvcObj.DeleteExtensionFileRecord strAppName
            bDel = True
        ‘End If
    End If
Next
  3. All you did is change the script to delete the Web Service Extension regardless if it is “read only” or not. This should allow you to subsequently run your iisext.vbs /RmFile command to do what you wanted.

Posted by | Filed Under Windows, Troubleshooting 

Someone else’s wireless network appears to be interfering with my own wireless connection

October 3, 2007 | Leave a Comment

Log into your router and change the channel it’s broadcasting on. Get as far away from the old number as possible.

If it’s at 1, go to 11.
If it’s at 11, go to 1.
If it’s at 6, go to 1, and if that doesn’t help try 11.

There are only 3 non-overlapping channels: 1, 6, and 11.

You can use a program like Netstumbler to see what channels are your neighbors are using. Use the one that is free or has the lowest db. This, of course, does not detect things like cordless phones, video transmitters, microwaves, etc. So you might actually find, say, channel one to be the best channel even if it has someone on it because your downstairs neighbor has a cordless phone on channel 6. Its interesting how often this happens and how “oh my neighbor is on his wireless again” can be coincidental.

Another thing to consider is to see if you can move your wireless device to a higher and more central location. I get full bars all the time because of smart positioning and by sprining for a nice high gain antenna for my desktop.

Posted by | Filed Under Networking, Troubleshooting