InFlook,116the Supreme Court considered the patentability of a method for updating alarm lim- its during a catalytic conversion process. Whereas the claimed invention inBensonsubsisted in an algorithm alone, the invention inFlookclaimed a mathematical algorithm as one step in the method. However, “[t]he only difference between the conventional methods of changing alarm limits and that described in [the] respondent’s application rests in . . . the mathematical algorithm or formula”.117 That is, the only advance over the prior art resides in the mathe-
matical algorithm. Thus the court characterised the central issue in this case as “whether the identification of a limited category of useful, though conventional, post-solution applications of such a formula makes respondent’s method eligible for patent protection”.118
The line between a patentable “process” and an unpatentable “principle” is not always clear. Both are “[conceptions] of the mind, seen only by [their] effects when being executed or performed.”Tilghman v Proctor102 US 707, 728119
In the end, the court found the claimed invention to be as non-patentable as the pure algorithm claimed inBenson. Their reasoning was that
[t]he notion that post-solution activity, no matter how conventional or obvious in it- self, can transform an non-patentable principle into a patentable process exalts form over substance. A competent draftsman could attach some form of post-solution ac- tivity to almost any mathematical formula.120
Despite this, however, the judgement inFlookcan be taken to have “backing down” fromBenson
in that the court expressly held the question of patentability open as follows:
Neither the dearth of precedent, nor this decision, should . . . be interpreted as re- flecting a judgement that patent protection of certain novel and useful computer programs will not promote the progress of science and the useful arts, or that such protection is undesirable as a matter of policy.121
The court also point out that it is not the mere existence of an algorithm in the claimed process which defeated the patentability of the invention. It was the fact that “once the algorithm is as- sumed to be within the prior art, the application, considered as a whole, contains no patentable invention”.122 115 Gottschalk v Benson409 US 63 (1973) at 71. 116 Parker v Flook437 US 584 (1978). 117 Parker v Flook437 US 584 (1978) at 586. 118 Parker v Flook437 US 584 (1978) at 585. 119 Parker v Flook437 US 584 (1978) at 589. 120 Parker v Flook437 US 584 (1978) at 590. 121 Parker v Flook437 US 584 (1978) at 595. 122 Parker v Flook437 US 584 (1978) at 594.
How software became patentable subject matter In re Freeman & In re Walter
In between the Supreme Court decisions inBensonandFlook and the later decision inDiehr, the CCPA developed a two-step test to determine whether claimed inventions containing algo- rithms should be considered patentable subject matter or not.
InFreeman,123the court dealt with the patentability of “a system for typesetting alphanumeric
information, using a computer-based control system in conjunction with a phototypesetter of conventional design,”124a system which was “especially useful in printing mathematical for-
mulae”.125 In determining whether Bensonprecluded patentability, the court resolved that a
two-step analysis was required:
First, it must be determined whether the claim directly or indirectly recites an ‘al- gorithm” in theBensonsense of that term, for a claim which fails even to recite an algorithm clearly cannot wholly pre-empt an algorithm. Second, the claim must be further analyzed to determine whether in its entirety it wholly pre-empts that algorithm.126
In discussing the first step, the court took a narrow view of the concept of an algorithm, re- quiring that the claims “recite process steps which are themselves mathematical calculations, formulae or equations”.127 The court discussed, but rejected, a broader definition, namely “a
step-by-step procedure for solving a problem or accomplishing some end”128on the basis that
“step-by-step solutions often attain the status of patentable inventions”.129 Since the claimed
invention did not involve any mathematical algorithms, it was held to fail the first step of the stated test, and hence to be patentable subject matter.
The main significance ofWalter130was that the CCPA modified the second step of theFreeman
test, moving away from the issue of pre-emption of an algorithm,131and focusing on the limit-
ing nature of the physical aspects of the claimed invention. The court restated the second test as follows:
If it appears that the mathematical algorithm is implemented in a specific manner to define structural relationships between the physical elements of the claim (in ap- paratus claims) or to refine or limit claim steps (in process claims), the claim passes muster under §101. If, however, the mathematical algorithm is merely presented and solved by the claimed invention, as was the case in BensonandFlook, and is not applied in any manner to physical elements or process steps, no amount of
123 In re Freeman573 F.2d 1243 (1978). 124 In re Freeman573 F.2d 1243 (1978) at 1238. 125 In re Freeman573 F.2d 1243 (1978) at 1239. 126 In re Freeman573 F.2d 1243 (1978) at 1245. 127 In re Freeman573 F.2d 1243 (1978) at 1246. 128 In re Freeman573 F.2d 1243 (1978) at 1245. 129 In re Freeman573 F.2d 1243 (1978) at 1245. 130 In re Walter618 F.2d 766 (1980). 131 In re Walter618 F.2d 766 (1980) at 767.
Chapter 3: How Software Became Patentable
post-solution activity will render the claim statutory; nor is it saved by a preamble merely reciting the field of use of the mathematical algorithm.132