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USL v. BSDi
This was a lawsuit brought in 1992 by UNIX System Laboratories (USL) against Berkeley Software Design
and the Regents of the University of California over intellectual property rights relating to
UNIX. The lawsuit eventually settled in 1993, and led to all sorts of interesting consequences for the
later history of UNIX.
The eventual outcome of the lawsuit (and the resulting settlement) turned on the prior history of UNIX,
so let us begin by reviewing the events leading up to the lawsuit.
- In 1970s, AT&T's Bell Labs began releasing versions of UNIX, and distributing and licensing it
in source code form.
Because, it was not clear at the time whether computer source code could be
copyrighted, AT&T generally relied upon a trade-secret theory to protect its intellectual property.
Source code either did not have copyright notices added, or perhaps even had them removed (so as to bolster
the claim that the source code was an unpublished trade secret).
Moreover, items published in the US without a copyright notice, prior to the Copyright Act of 1976, were
- Despite taking the position that the source code contained unpublished trade secrets, AT&T distributed
and licensed the source code widely, including to many universities. Many thousands of students worked with
the source, analysis and code snippets were published in text books, and a US standard (POSIX) was even created based on the programming interfaces ("API").
- Source code licensees often developed add-on programs or modifications. AT&T made clear in their newsletter,
that they claimed no copyright or ownership interest in the licensee's source code except to the extent that it
contained elements of AT&T's source code.
- One licensee of the source code was the University of California, Berkeley (UC Berkeley). Students at the
Computer Systems Research Group (CSRG) modified and
enhanced the AT&T source code, and made releases of their modified operating system. Initially, the modified
operating system was only made available to other AT&T licensees (and this was done with AT&T's blessing).
However in 1992, after a processing of auditing, removing, and replacing AT&T source code, CSRG believed they
had developed a complete UNIX-like operating system (which they called NET-2) containing no AT&T intellectual
property. NET-2 was released under the original version of the BSD License
(with the advertising clause.
- AT&T's subsiduary, UNIX System Laboratories (USL), sused Berkeley Software Design, Inc. (BSDi) and the Regents of the University of California, alleging (among other things) that NET-2 infringed the USL's copyright on UNIX and divulged USL's trade secrets in UNIX, and the claim that NET-2 "contained no AT&T licensed code" was false. Furthermore, USL asked for a preliminary injunction that would bar the distribution of the NET-2 software until the case
- The arguments made by the Regents of the University California made against the preliminary injunction relied on whether AT&T had valid copyrights on older
versions of UNIX, whether it had abandoned copyrights on additional parts of UNIX (for example by allowing text books to be published, and whether certain code was mandated by standards set by outside organizations such as POSIX (which AT&T endorsed) meaning that such code could no longer be considered to be a creative work. In summary, the university claimed
that they had removed all the validly copyrighted AT&T UNIX code, but even if they had missed AT&T code, these
amount to such as a small fraction of NET-2 that NET-2 could not be legally considered a derived work.
- The University also filed a separate lawsuit against USL, alleging that USL had violated its license to BSD code written at UC Berkeley. AT&T had in fact signed an express license agreement with the University, and one of
the requirements of this was AT&T's compliance with the advertising clause of the BSD license. However, USL
had made UNIX releases prior to the lawsuit that did not contain the required copyright notices and author
- The case settled in 1994, by which point the judge refused to grant USL a preliminary injunction and
the UNIX intellectual property had been purchased by
- The terms of settlement were keep secret at the time, but in 2004, they were eventually published online.
After the lawsuit, NET-2 was replaced by 4.4BSD-lite, which was similar but not identical to NET-2 (out of 18,000
files, only 3 files were removed, and 70 files modified to show USL copyright notices), and which
both BSDi and AT&T agreed did not contain any disputed files.
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