Few domains of intellectual property have given rise to as many concerns and misunderstandings as the question of software patentability. At P&TS, we follow very closely the evolution of the jurisprudence on this question which we have made into one of our favorite specialties.
Computer programs are protected without any formalities by copyright, in the same manner as works of art. Copyright however protects only the program's code, independently from its function. A program executing the same algorithm but implemented with a different series of instructions will thus generally not be considered an infringement of the copyright, unless it is a literal transcompilation (re-writing the program in a different computer language).
The legislation of several countries furthermore provides for copyright protection of flux diagrams underlying a program or for certain elements of the graphical interface of the program (data display, original icons, menu titles etc.). The conditions are often rather strict and it is necessary to verify on a case by case basis with the assistance of a specialist which elements of a program are protected in which country.
Most states accept nowadays the patentability of software and computer programs. The protection obtained is generally wider than that given by copyright since a patent can protect the function achieved by a software, independently from the code. In Europe, it is however necessary for the program to have a technical effect. The patentability is furthermore dependent on the specific wording of the claims.
The USA have adopted a more liberal approach and also grant patents for software implementing in fact business methods.