Structure, sequence and organization

Structure, sequence and organization (SSO) is a term used in the United States to define a basis for comparing one software work to another in order to determine if copying has occurred that infringes on copyright, even when the second work is not a literal copy of the first. The term was introduced in the case of Whelan v. Jaslow in 1986. The method of comparing the SSO of two software products has since evolved in attempts to avoid the extremes of over-protection and under-protection, both of which are considered to discourage innovation. More recently, the concept has been used in Oracle America, Inc. v. Google, Inc.

Whelan Assocs., Inc. v. Jaslow Dental Laboratory, Inc. was a landmark case in defining principles that applied to copyright of computer software. Whelan had developed software for Jaslow to manage the operations of a dental laboratory, and later took it to market under the trade name Dentalab. Jaslow became engaged in selling the Dentalab software. He later formed a new company named Dentcom and wrote a program in a different computer language but with similar functionality that he called Dentlab, marketing it as a Dentalab successor. Whelan filed a suit in federal court in Pennsylvania alleging that the Dentlab software violated Whelan's copyrights in the Dentalab software. Whelan won the case and was awarded damages on the basis that Dentlab had substantially similar structure and overall organization.

The district court ruling in Whelan drew on the established doctrine that even when the component parts of a work cannot be copyrightable, the structure and organization of a work may be. The court also drew support from the 1985 SAS Inst. Inc. v. S&H Computer Sys. Inc. in which it had been found that copyright protected organizational and structural details, not just specific lines of source or object code. Sequence, structure and organization (SSO) in 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.". However, the SAS Inst. Inc. V. S&H Computer Sys. Inc. demonstrated that copyright can exist in derived works from publicly funded developed source code in the public domain rather than address the issue of SSO.

Jaslow appealed the decision. The Court of Appeals for the Third Circuit noted that computer programs are literary works under U.S. law. 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, although 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.

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