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In re Knowlton, 481 F.2d 1357, 178 U.S.P.Q. (BNA) 486 (C.C.P.A. 1973) (full-text).

Factual Background[]

Knowlton invented a method for digital computer processing of linked list files with variable length records, and claimed it as a "machine" in means-plus-function language. The specification disclosed block diagrams and program listings and a description thereof, with "disclosure of the preferred embodiment of the invention . . . made up of a number of computer program listings."[1]

Additionally, the disclosure went into "considerable detail" concerning the interrelationship between the hardware elements. The specification also identified an "IBM 7094 Data Processing System" as one type of apparatus which could process the listed programs.[2]

The Patent Office contended that to properly disclose the invention, the application would "not only have to include a detailed description of the circuits" of the computer, but would "also have to include a detailed description of the physical state such circuit would be placed in by the disclosed program."

Board of Appeals Proceedings[]

The Board affirmed.

C.C.P.A. Proceedings[]

The C.C.P.A. rejected the "multiple recitation” attack on the claim language.[3] An effort by the Government to burden program-related apparatus claims with heavy disclosure requirements also suffered defeat.[4]


The Board of Patent Appeals and Interferences had acted on the Knowlton case before the decision in Gottschalk v. Benson.[5] The Patent Office thereby lost an excellent opportunity to extend the Benson holding to apparatus claims, since the essential facts in Knowlton seem to fall squarely within the Supreme Court's reasoning.


  1. Id. at 1358-61, 178 U.S.P.Q. (BNA) at 487-89.
  2. Id.
  3. Id. at 1367-68, 178 U.S.P.Q. (BNA) at 493-94.
  4. Id. at 1367, 178 U.S.P.Q. (BNA) at 494.
  5. 409 U.S. 63 (1972) (full-text).