COMDB - List and Release unused COM ports
-----------------------------------------

A Win32 console utility that prints a list of COM ports 
allocated to some drivers in the system. It allows to release 
any currently unused COM ports so that they can be allocated
by newly installed drivers again. 

Note that the correct way is to uninstall the driver that 
occupies the ports, which should result in freeing allocated
ports. However, in practice, it does not seem to that easy.

Be aware though that using this application you may gain 
some inconsistent state, so use it only at your own risk.

Typical situation when you need this program: 
     
You have installed some virtual serial ports, which you do not use anymore
and removed the application that allocated them, but the ports are still
occuppied and busy. At the same time, you have an application that does
not handle ports higher than COM9 and all COM1-COM9 are already occuppied.
Use this program to free those locked ports that are not used anymore.

To compile the program, you need WinDDK (Windows Driver Kit) from Microsoft, 
which can be downloaded for free, but it is very large (more than 600MB). 

Robotika.SK, 2007.
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