this case was defined as "the manner in which the program operates, controls and regulates the computer in receiving, assembling, calculating, retaining, correlating, and producing useful information." SSO refers to non-literal elements of computer programs that include "data input formats, file structures, design, organization and flow of the code, screen outputs or user interfaces, and the flow and sequencing of the screens." Decision The Court of Appeals for the Third Circuit noted that computer programs are literary works under U.S. law. The court drew an analogy with a concept defined by Judge Learned Hand who noted, talking about a play, that the exact wording was certainly protected, and then there were a series of layers of increasing abstraction before the high-level plot outline is reached, which is not protected. An ad hoc judgement based on careful comparison of the works would be needed to determine where in this spectrum any alleged copying lay, and to decide whether it was at a sufficiently specific level to be a violation rather than a different expression of the same idea. But "careful comparison" in the case of software works might involve checking millions of lines of code. The court rejected the "extrinsic-intrinsic" test that had commonly been used until then, where an expert and a lay observer are asked to independently determine whether the works are substantially similar. The court reasoned that with literary works a non-literal element is protected to the extent that it is an expression of an idea rather than the idea itself. By analogy, the purpose or function of a software work would be the work's "idea", while everything not necessary to that purpose or function would be part of the expression of the idea. The expression would be protected, but the basic purpose or function would not. On this basis the Court of Appeals upheld the district court's ruling of copyright violation due to similarity of SSO. The court found that the Copyright Act of 1976 supported its view of a software work as a compilation, saying: Results The Whelan decision initiated a period of excessively tight protection, suppressing innovation, since almost everything other than the broad purpose of a software work would be protected. The only exception was where the functionality could only be achieved in a very small number of ways. In these cases there could be no protection due to the merger doctrine, which applies