1992)[1] is a decision from the United States Court of Appeals for the Second Circuit that addressed to what extent non-literal elements of software are protected by copyright law.

Finally, the district court concluded that Computer Associates' state law trade secret misappropriation claim against Altai was preempted by the federal Copyright Act.

The Second Circuit affirmed the district court's ruling as to copyright infringement, but vacated and remanded its holding on trade secret preemption.

In 1982, Altai established their own job scheduler called ZEKE written for the VSE operating system.

In efforts to create a version of ZEKE to run on the MVS operating system, Altai employee James Williams recruited his longtime friend Claude Arney, an employee of Computer Associates, to create the MVS version.

Arney left CA to work on Altai's ZEKE program, taking the VSE and MVS versions of the source code for ADAPTER with him.

In the judgment of the United States District Court for the Eastern District of New York, the Honorable George C. Pratt, United States Circuit Judge found that OSCAR 3.4 was a copyright infringement of CA's CA-SCHEDULER and awarded CA $364,444 in damages and apportioned profits.

They claimed that the district court did not apply a proper test that took into consideration the copying of non-literal elements of computer software.

They claimed that despite the clean room rewrite, there was substantial similarity in the structures of ADAPTER including flow charts, inter-modular relationships, parameter lists, macros, and services obtained from the operating system.

To approach this issue, the court fully supported the claim that non-literal elements of software are protected under copyright.

The court agreed with the opinion in Baker v. Selden which stated that things that "must necessarily be used as incident to" the idea are not subject to copyright protection.

As an alternate metric, the court presented a three-step test to determine substantial similarity, abstraction-filtration-comparison.

This process is based on other previously established copyright principles of merger, scenes a faire, and the public domain.

[1] In this test, the court must first determine the allegedly infringed program's constituent structural parts.

CA and other large computer companies argue that without broader protection, the test will stifle development and disincentivize programmers from actively designing and improving programs.