Com0com

com0com is a free utility to create virtual serial port pairs which can be used to capture the debug output of ReactOS and direct it to a terminal program.

Useful terminal programs that are able to get this output include:

• Hyper Terminal
• Teraterm
• Putty
• Hercules
• ReactOSDbg

Setup

Get com0com and install it. It will automatically install a pait of virtual COM ports "\\.\CNCA0" and "\\.\CNCB0" that are linked by a virtual null modem cable.

You can optionally change the names and edit the settings with the gui setup tool (setupg.exe).

Connecting the virtual machine and terminal application

Connect the Virtual Machine to your first virtual port ("COM4") and the terminal application to the second ("COM5").

The properties of the serial port (usually specified in the virtal machine), like the baud rate, are not important. Instead, be sure to select "NO FLOW CONTROL", because otherwise the terminal app won't receive any characters.

What does com0com do?

The virtual machine shows a COM1 port to ReactOS which is used for sending debug messages.

The virtual machine maps this port to a virtual port visible to the host operating system.

com0com emulates a null modem cable between the vm and the terminal application.