Computer Associates Int'l, Inc. v. Altai, Inc.
982 F.2d 693 (2d Cir. 1992)
CA wrote a computer program
that would allow their scheduling software to run on different kinds of
computers. Altai sold a similar kind of scheduling software, so they
asked their programmers (who were kept segregated from CA's program), to
write a program with the same functionality, which they did.
CA sued Altai for copyright
The Trial Court found for
Altai. CA appealed.
The Appellate Court affirmed.
The Appellate Court looked
to Baker v. Selden (101 U.S. 99
(1879)), and noted that an idea cannot be copyrighted, only
the expression of that idea can be copyrighted.
The Court applied the Abstraction
- Filtration - Comparison test.
In Abstraction the court breaks up the program into
different levels, from very general to very specific.
E.g. Main purpose, program
structure, modules, algorithms, data structures, source code.
In Filtration, the court decides what components are
absolutely essential to fulfilling the abstract function of the program
at the various levels.
Also filter out everything
that is dictated by efficiency, external factors, or in the public
In Comparison, the court looks at the components of the
program which are not absolutely essential to fulfilling the abstract
function of the program to see if they are similar.
The Court performed the Abstraction
- Filtration - Comparison test and
found that the copyrightable elements from CA's program were not substantially
similar to those elements in Altai's
Basically, this case said that
what the courts need to do is to sift out all elements of the allegedly
infringed program which was ideas of dictated by efficiency or external
factors, or taken from the public domain in order to find "a core of
protectable expression." At that point the courts should focus on
whether there are substantial similarities between any elements within this core in the two programs.