This question is very hot in many chat rooms at the moment ' and nobody really knows what it is. But from what I can gather it is a computer programme that is installed on your PC when you have a cable modem installed (most often from the @Home network, but not always). They are believed to be programmes licensed by Tioga Systems Ltd to help with configuration problems on your computer, so that if you have problems with your modem or internet connection and you call the @Home helpline for instance they can access this information. Tioga takes a snapshot of info on your PC upon installation and gives a verification on a working connection to the Internet. The Tioga software identifies itself on your PC as tgcmd, sometimes as tgcmd.exe.
Lots of people believe that it is spyware so that your PC can be hacked into, but as far as I am concerned this is just paranoia. If having it on your PC is causing problems, e.g. making it crash then remove it, it will not harm the workings of your system. Alternatively, install a firewall and deny it access to the Internet if you think it is spying on you.