Clean room design

Clean-room design (also known as the Chinese wall technique) is the method of copying a design by reverse engineering and then recreating it without infringing any of the copyrights associated with the original design. Clean-room design is useful as a defense against copyright infringement because it relies on independent creation. However, because independent invention is not a defense against patents, clean-room designs typically cannot be used to circumvent patent restrictions.

This article is about the design-copying technique. For the manufacturing or research environment, see clean room. For the software development methodology, see cleanroom software engineering.

The term implies that the design team works in an environment that is "clean" or demonstrably uncontaminated by any knowledge of the proprietary techniques used by the competitor.

Typically, a clean-room design is done by having someone examine the system to be reimplemented and having this person write a specification. This specification is then reviewed by a lawyer to ensure that no copyrighted material is included. The specification is then implemented by a team with no connection to the original examiners.

Examples

Phoenix Technologies sold its clean-room implementation of the IBM-compatible BIOS to various PC clone manufacturers.[1][2]

Several other PC clone companies, including Corona Data Systems, Eagle Computer, and Handwell Corporation, were successfully sued by IBM for copyright infringement in 1984, and were forced to re-implement their BIOS in a way which did not infringe IBM's copyrights.[3][4]

These three settlements happened before Phoenix announced in July of that year that they were licensing their own BIOS code, expressly emphasizing the clean-room process through which Phoenix's BIOS code had been written by a programmer who did not even have prior exposure to Intel microprocessors, himself having been a TMS9900 programmer beforehand.[5] As late as the early 1990s, IBM was winning millions of dollars from settling BIOS copyright infringement lawsuits against some other PC clone manufacturers like Matsushita/Panasonic (1987)[6] and Kyocera (1993–1994), although the latter suit was for infringements between 1985 and 1990.[7][8]

Another clean-room design example is VTech's successful clones of the Apple II ROMs for the Laser 128, the only computer model among dozens of Apple II compatibles which survived litigation brought by Apple Computer.

Other examples include ReactOS, an open source operating system made from clean-room reverse-engineered components of Windows, and Coherent operating system, a clean room re-implementation of version 7 Unix.[9] In the early years of its existence, Coherent's developer Mark Williams Company received a visit from an AT&T delegation looking to determine whether MWC was infringing on AT&T Unix property.[10] It has been released as open source.[9]

Case law

Clean room design is usually employed as best practice, but not strictly required by law. In NEC Corp. v Intel Corp. (1990), NEC sought declaratory judgment against Intel's charges that NEC's engineers simply copied the microcode of the 8086 processor in their NEC V20 clone. A US judge ruled that while the early, internal revisions of NEC's microcode were indeed a copyright violation, the later one, which actually went into NEC's product, although derived from the former, were sufficiently different from the Intel microcode it could be considered free of copyright violations. While NEC themselves did not follow a strict clean room approach in the development of their clone's microcode, during the trial, they hired an independent contractor who was only given access to specifications but ended up writing code that had certain similarities to both NEC's and Intel's code. From this evidence, the judge concluded that similarity in certain routines was a matter of functional constraints resulting from the compatibility requirements, and thus were likely free of a creative element.[11] Although the clean room approach had been used as preventative measure in view of possible litigation before (e.g. in the Phoenix BIOS case), the NEC v. Intel case was the first time that the clean room argument was accepted in a US court trial. A related aspect worth mentioning here is that NEC did have a license for Intel's patents governing the 8086 processor.[12]

Sony Computer Entertainment, Inc. v. Connectix Corporation was a 1999 lawsuit which established an important precedent in regard to reverse engineering.[13][14] Sony sought damages for copyright infringement over Connectix's Virtual Game Station emulator, alleging that its proprietary BIOS code had been copied into Connectix's product without permission. Sony won the initial judgment, but the ruling was overturned on appeal. Sony eventually purchased the rights to Virtual Game Station to prevent its further sale and development. This established a precedent addressing the legal implications of commercial reverse engineering efforts.

During production, Connectix unsuccessfully attempted a Chinese wall approach to reverse engineer the BIOS, so its engineers disassembled the object code directly. Connectix's successful appeal maintained that the direct disassembly and observation of proprietary code was necessary because there was no other way to determine its behavior. From the ruling:

Some works are closer to the core of intended copyright protection than others. Sony's BIOS lay at a distance from the core because it contains unprotected aspects that cannot be examined without copying. The court of appeal therefore accorded it a lower degree of protection than more traditional literary works.

  • In the 2014 TV show Halt and Catch Fire a key plot point from the second episode of the first season is how the fictional Cardiff Electric computer company placed an engineer, and primary character, in a clean room to reverse engineer a BIOS for their PC clone, to provide cover and protection from IBM lawsuits for a previous probably-illegal hacking of the BIOS code others at the company had performed.
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See also

References
  1. Schwartz, Mathew (2001-11-12). "Reverse-Engineering". computerworld.com. Retrieved 2013-06-23. To protect against charges of having simply (and illegally) copied IBM's BIOS, Phoenix reverse-engineered it using what's called a "clean room," or "Chinese wall," approach. First, a team of engineers studied the IBM BIOS—about 8KB of code—and described everything it did as completely as possible without using or referencing any actual code. Then Phoenix brought in a second team of programmers who had no prior knowledge of the IBM BIOS and had never seen its code. Working only from the first team's functional specifications, the second team wrote a new BIOS that operated as specified.
  2. Bernard A. Galler (1995). Software and Intellectual Property Protection: Copyright and Patent Issues for Computer and Legal Professionals. Greenwood Publishing Group. p. 130. ISBN 978-0-89930-974-3.
  3. Caruso, Denise (February 27, 1984), "IBM Wins Disputes Over PC Copyrights", InfoWorld, p. 15, retrieved February 28, 2011
  4. Sanger, David E. "EAGLE'S BATTLE FOR SURVIVAL".
  5. "Phoenix Says Its BIOS May Foil IBM's Lawsuits". Pc Magazine : The Independent Guide to Ibm-Standard Personal Computing. Ziff Davis, Inc.: 56 10 July 1984. ISSN 0888-8507.
  6. "Matsushita, IBM settle BIOS copyright infringement dispute". Computerworld : The Newspaper for It Leaders. Computerworld: 67. 2 March 1987. ISSN 0010-4841.
  7. Pollack, Andrew. "COMPANY NEWS; Japanese Company Is Sued By I.B.M. Over Copyrights".
  8. Joseph W. S. Davis; Hiroshi Oda; Yoshikazu Takaishi (1996). Dispute resolution in Japan. Kluwer Law International. pp. 248–254. ISBN 978-90-411-0974-3.
  9. "Coherent sources released under a 3-clause BSD license – Virtually Fun". virtuallyfun.com. Retrieved 20 September 2018.
  10. Dennis Ritchie (April 10, 1998). "Re: Coherent". Newsgroup: alt.folklore.computers. Usenet: 352DC4B7.3030@bell-labs.com.
  11. Jorge Contreras, Laura Handley, and Terrence Yang, "NEC v. Intel : Breaking New Ground in the Law of Copyright, Harvard Journal of Law & Technology, Volume 3, Spring Issue, 1990, pp. 209–222 (particularly p. 213)
  12. David S. Elkins, “NEC v. Intel: A Guide to Using "Clean Room" Procedures as Evidence”, Computer Law Journal, vol. 4, issue 10, (Winter 1990) pp. 453–481
  13. Sony Computer Entertainment, Inc. v. Connectix Corporation, 203 F.3d 596 (9th Cir. 2000).
  14. Sony Computer Entertainment, Inc. v. Connectix Corporation, 203 F.3d 596 (9th Cir. 2000). Web Archive.org copy, Feb 28, 2007.

Further reading
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