Depending on jurisdiction, technically, a trade mark ™ is established by use, for the tort of passing off. A registered trademark uses the encircled R symbol: ®

Depending on jurisdiction, technically, a trade mark ™ is established by use, for the tort of passing off. A registered trademark uses the encircled R symbol: ® You may be thinking of copyright, which at one time did not explicitly include computer programs as protected works, depending on jurisdiction.