I am not certain. But even when a trademark its registration has not been extended by the trademark owner. Then I am do not think you can just use.
As IBM still retains ownership of the word OS/2. This might also vary from region to region in the world.
Roderick
No, that applies to copyrights and automatic grants of IP ownership in general (for most countries anyway, those that are fully signed up to the Berne convention). Trademarks are different, they have some aspects of IP but are mostly grants of goodwill, you have to register them, keep the registration current and defend them, otherwise you lose the exclusive rights to use them.
IBM & MS can object to you registering the OS/2 trademark, but they will have to show that they are currently using it, show that you are not currently using it and are thus attempting to register it in bad faith, and will have to show a valid reason for not having maintained the trademark registration. They cannot stop you from using it on t-shirts or other products, since they no longer have any claim on it.
The CE world is full of trademarks that have at one time been taken over by unrelated companies or individuals by re-registering the trademark rather than buying them from a trademark owner, for example Nikko, Telefunken, Universal Audio, Moog, Scott, Audio Note, etc.
