Inventions involving programs for computers can be protected in different forms of a "computer-implemented invention", an expression intended to cover claims which involve computers, computer networks or other programmable apparatus whereby prima facie one or more of the features of the claimed invention are realised by means of a program or programs. Such claims directed at computer-implemented inventions may e.g. take the form of a method of operating said apparatus, the apparatus set up to execute the method, or, following T 1173/97 (OJ 1999, 609), the computer program itself as well as the physical media carrying the program (see T 424/03), i.e. computer program product claims, such as "data carrier", "storage medium", "computer readable medium" or "signal" (Guidelines G‑II, 3.6 – November 2015 version).
Art. 52(3) EPC establishes an important limitation to the scope of this exclusion. According to this provision, the exclusion applies only to the extent to which a European patent application or a European patent relates to programs for computers "as such". In T 935/97 the board stated that the combination of the two provisions (Art. 52(2) and (3) EPC 1973) demonstrates that the legislators did not want to exclude from patentability all programs for computers. In other words the fact that only patent applications relating to programs for computers as such are excluded from patentability means that patentability may be allowed for patent applications relating to programs for computers where the latter are not considered to be programs for computers as such.
According to the early case law of the boards of appeal, the view was taken on a number of occasions that exclusion under Art. 52(2)(c) and (3) EPC 1973 applied to all computer programs, independently of their contents, that is, independently of what the program could do or perform when loaded into an appropriate computer (see T 1173/97; OJ 1999, 609). To make a distinction between programs with a technical character and those with a non-technical character would not be allowed under such reasoning. Some examples of such reasoning could be found for instance in decisions T 26/86 (OJ 1988, 19, point 3.1 of the Reasons), T 110/90 (OJ 1994, 557, point 5 of the Reasons), and T 204/93 (point 3.13 of the Reasons). For example, in T 204/93, the board held that computer programs as such, independent of their application, were not patentable irrespective of their content, even if that content happened to be such as to make it useful, when run, for controlling a technical process. The board ruled that, "similarly", a programmer's activity of programming was, "as a mental act", not patentable, irrespective of whether the resulting program could be used to control a technical process, and that automating that activity in a way which did not involve any unconventional means did not render that programming method patentable either, independently of the content of the resulting program.