SCO Group, Inc. v. International Business Machines Corp.

The SCO Group, Inc.
Company type	Public
Industry	Software
Predecessor	Caldera International, Caldera Systems
Fate	Filed for bankruptcy in 2007
Headquarters	United States
Area served	Worldwide
Key people	Darl McBride (CEO)
Products	UNIX operating system software

SCO Group, Inc. v. International Business Machines Corp. (commonly known as SCO v. IBM) represents a civil lawsuit initiated in 2003 within the United States District Court for the District of Utah. The SCO Group asserted legal disputes regarding the use of the Linux operating system, alleging that IBM breached Unix licensing agreements while contributing to Linux development. The litigation continued through SCO's bankruptcy and an unfavorable verdict in SCO v. Novell, before being reopened by a different judge on June 14, 2013.

After reopening, IBM submitted a Motion for Summary Judgment grounded on the Novell case ruling. On December 15, 2014, the court approved the majority of IBM’s motion, thereby limiting the litigation’s scope. Following a decision dismissing SCO’s remaining allegations, the judge terminated the lawsuit with prejudice on March 1, 2016. SCO filed an appeal later that month.

In February 2018, after a partial remand to the appellate court, both parties restated their claims and presented a framework for final judgment. The dispute ultimately concluded with a settlement reached in 2021.

Summary

On March 6, 2003, the SCO Group (previously known as Caldera International and Caldera Systems) launched a $1 billion lawsuit against IBM, accusing IBM of diminishing the value of its UNIX operating system. SCO engaged Boies Schiller & Flexner to handle this and related legal matters. The damages claimed escalated to $3 billion and later $5 billion. SCO charged IBM with unauthorized incorporation of SCO’s intellectual property into the open source Unix-like Linux codebase. In May 2003, SCO issued warnings to members of the Fortune 1000 and Fortune Global 500 about potential legal risks associated with Linux usage.

The conflict intensified as IBM and Linux distributor Red Hat initiated counter-litigation against SCO, while SCO threatened Linux users over UNIX licensing issues and filed lawsuits against companies such as Novell, AutoZone, and DaimlerChrysler.

On September 30, 2003, Judge Kimball approved SCO’s motion to postpone filings until February 4, 2004; this schedule was subsequently revised on July 1, 2005. In December 2006, the trial was deferred pending resolution of SCO v. Novell, which was anticipated to clarify matters relevant to SCO v. IBM.

On June 28, 2006, Judge Brooke Wells restricted SCO’s claims by excluding 187 out of 298 alleged infringements for lack of detail. Wells criticized SCO’s imprecise approach, likening it to accusing someone of theft without identifying the stolen items.

On August 10, 2007, Judge Kimball determined that Novell—not SCO—held ownership of the Unix copyrights and ruled that SCO must acknowledge Novell’s waiver of claims against IBM and Sequent. Novell declared it had no intention to pursue litigation concerning Unix and stated "We don't believe there is Unix in Linux."

Following SCO’s bankruptcy filing on September 14, 2007, Judge Kimball administratively closed SCO v. IBM on September 21, suspending proceedings until bankruptcy matters were resolved.

On August 24, 2009, the U.S. Court of Appeals for the Tenth Circuit overturned part of the 2007 decision in SCO v. Novell, permitting SCO to continue pursuing copyright ownership claims at trial.

Finally, on March 30, 2010, a jury concluded that Novell retained ownership of the Unix copyrights.

SCO's allegations

Since early 2004, SCO's litigation has primarily centered on breach of contract allegations, having previously abandoned claims related to trade secret theft. Initially, SCO asserted the following:

Theft of trade secrets
Unfair competition
Contractual interference
Violation of the IBM Software Agreement

On July 22, 2003, additional claims were introduced:

Breach of the IBM Sublicensing Agreement
Breach of the Sequent Software Agreement

By February 27, 2004, SCO withdrew its trade secret accusations but added new charges:

Breach of the Sequent Sublicensing Agreement
Copyright infringement
Interference with business relationships

SCO’s public messaging has been inconsistent, with contradictory statements about whether the alleged copyright violations pertain to the Linux kernel. CEO Darl McBride claimed that "hundreds of lines" of SCO UNIX code were embedded within the Linux kernel and pledged to disclose details under a non-disclosure agreement (NDA). However, Linux developers rejected SCO’s NDA terms due to their overly restrictive nature, which would have required confidentiality even regarding previously public information. During SCO’s 2003 reseller event, brief excerpts of code were displayed openly.

The Linux 2.4.2 kernel was estimated to contain approximately 2.4 million lines of source code; initially, SCO asserted that the infringing portion was an extremely small fraction (~0.001%), but later escalated this figure to over one million lines. SCO’s principal assertions involve Linux kernel components such as:

Symmetric multiprocessing (SMP)
Non-uniform memory access (NUMA) multiprocessing
The read-copy-update (RCU) locking mechanism—believed to have originated at Sequent Computer Systems, later acquired by IBM, which holds patents (e.g., patent ) covering it
Silicon Graphics’ (SGI) Extended File System (XFS)
IBM’s JFS journaling file system

These claims are grounded in alleged breaches of contracts concerning IBM’s utilization of SVR4 code under agreements with AT&T, to which SCO asserts successor rights. IBM interprets "derivative works" narrowly as those containing SVR4 code and thus confidential; in contrast, SCO contends this term encompasses all code developed based on SVR4—even if it does not contain SVR4 code itself—implying that all IBM-developed AIX operating system code must be treated as confidential.

Response from free software and open source communities

The lawsuit provoked a strong backlash within free software and open source circles, who generally regarded SCO’s allegations as unfounded and misleading. The main counterarguments include:

Despite SCO’s claim to be "The owner of the UNIX operating system," ownership of the disputed code is unclear; this was supported by the jury verdict in SCO v. Novell.
Linux was created independently by numerous contributors with a transparent development history, making it improbable that it contains SCO UNIX code.
Many Linux features predate similar ones in SCO UNIX, undermining any copying claims.
Shared code might have originated from other open source projects like BSD or earlier UNIX versions that were publicly released by SCO.
Caldera Systems initially focused on Linux before acquiring SCO’s UNIX assets and incorporating Linux-like features into SCO UNIX; some code may have been copied from Linux into SCO UNIX.
- Should reverse copying be proven, SCO might be compelled either to withdraw products containing GPL-licensed code or release their source under GPL terms.
The UNIX source code had been broadly accessible without confidentiality restrictions, weakening trade secret claims.
SCO distributed Linux under the GPL through Caldera OpenLinux, which diminishes its legal standing to sue other Linux users.

SCO and its leadership faced considerable criticism from the free software community. SEC filings revealed that senior executives sold personal stock holdings shortly after IBM and Red Hat filed counterclaims. CEO Darl McBride attracted particular attention for his confrontational public remarks.

On March 10, 2003, the Open Source Initiative (OSI) published a position paper addressing the SCO v. IBM lawsuit, authored by OSI president Eric S. Raymond.

Starting May 16, 2003, Groklaw—founded by journalist and paralegal Pamela Jones—provided daily coverage of the case, becoming a vital resource for community engagement and legal commentary. The SCO Group identified Groklaw as a significant adversary.

On May 30, 2003, Linux creator Linus Torvalds dismissed the lawsuit as a public spectacle.

In June 2003, an anonymous Linux kernel developer threatened legal action against SCO for distributing a Linux variant allegedly containing non-GPL-compliant code; no public response from SCO is known.

Torvalds also defended Linux development practices against SCO’s critiques in June 2003, highlighting transparency and thorough tracking of code origins.

On June 27, 2003, Eben Moglen of the Free Software Foundation reaffirmed that SCO’s trade secret claims lacked validity since SCO had commercially distributed Linux under licenses permitting unrestricted copying.

On July 31, 2003, the Open Source Development Labs issued a position paper authored by Eben Moglen that reiterated these points and emphasized the weakness of SCO’s legal arguments.

Allegations of Spreading Fear, Uncertainty, and Doubt

Numerous advocates within the Linux community have accused SCO of deliberately fostering fear, uncertainty, and doubt surrounding Linux. Some observers speculated that SCO's underlying intention was to position itself for acquisition by IBM. Additionally, there were claims that Microsoft's licensing agreement with SCO over its source code might have been a form of quid pro quo linked to SCO's legal maneuvers.

In May 2003, Univention GmbH, a company specializing in Linux integration, revealed that a Bremen court issued an injunction under German antitrust law. This order barred SCO’s German branch from asserting that Linux contained SCO intellectual property obtained unlawfully, with a penalty of €250,000 imposed for any breaches. A comparable injunction was sought in Poland as well.

On July 23, 2003, Open Source Victoria submitted a formal complaint to the Australian Competition & Consumer Commission. The complaint called for scrutiny of SCO’s unverified allegations and alleged coercive legal threats directed at Australian Linux users.

On November 13, 2003, SCO issued subpoenas targeting Richard Stallman and Linus Torvalds.

Issues Surrounding the GPL

Shortly after initiating the lawsuit, Eben Moglen, then serving as legal advisor to the Free Software Foundation, clarified that SCO’s litigation was chiefly aimed at IBM rather than the broader Linux community. In an interview with internetnews.com, he expressed this viewpoint:

Acknowledging the inconsistency of distributing a Linux product while simultaneously suing IBM over intellectual property purportedly embedded in Linux, SCO declared on May 14, 2003, its intention to halt further Linux distribution. The company committed to "continue supporting existing customers of SCO Linux and Caldera OpenLinux and to protect them from any SCO intellectual property claims related to these products."

SCO contends that any code it alleges was licensed under the GPL was done so without proper authorization by its employees and is therefore not legitimately GPL-licensed. Their position holds that for code to be licensed under the GPL, the copyright holder must explicitly apply a GPL notice—a step SCO asserts it never authorized.

The GPL and Constitutional Considerations

During its legal battle with IBM, SCO asserted that the GPL conflicted with the United States Constitution, a claim which they withdrew in April 2004. Their argument centered on Article One, Section 8, which empowers Congress to grant exclusive rights to authors and inventors. SCO argued that the GPL’s extensive licensing terms effectively waived exclusive rights, thereby clashing with this constitutional provision.

This stance challenges both Congress’s authority in crafting copyright legislation and the ability of rights holders to control their intellectual property. However, since the GPL restricts distribution in jurisdictions that do not comply with its terms, a ruling favoring SCO could potentially hinder Linux distribution within the United States.

Legal analysts have largely dismissed SCO’s constitutional assertions as lacking merit. Intellectual property lawyer Tom Carey described attacks on the GPL as "far-fetched and somewhat desperate." Industry analyst Stacey Quandt compared SCO’s claims to Microsoft’s prior critiques of open source software as "utterly baseless."

Eben Moglen—FSF counsel and principal drafter of the GPL—characterized SCO’s constitutional challenge as more of a public relations maneuver than a credible legal argument. During a 2004 Harvard address, he emphasized that Congress’s extension of copyright durations demonstrated there is no unconstitutional copyright rule if legislation is properly enacted while respecting the distinction between expression and ideas.

Novell's involvement in the dispute

On May 28, 2003, Novell became actively involved in the conflict by issuing a statement that contested SCO Group's assertions regarding UNIX ownership. Novell maintained that the 1995 transaction transferring UNIX rights to SCO did not encompass the copyrights, and that SCO’s multiple attempts to obtain copyright ownership had been consistently denied.

SCO subsequently contended that a contractual amendment had partially conveyed copyrights to them. While Novell confirmed the amendment's existence, it reported being unable to locate its copy and argued in December 2003 that the conditions for the transfer were not fulfilled by SCO.

SCO rejected Novell’s claims. On January 20, 2004, SCO initiated SCO v. Novell. Then, on August 10, 2007, Judge Kimball ruled in favor of Novell’s ownership of UNIX and UnixWare copyrights, enabling Novell to instruct SCO to relinquish claims against IBM and Sequent—an outcome that notably influenced related legal proceedings.

IBM’s license for AIX

In June 2003, SCO threatened to terminate IBM’s license to utilize UNIX code within AIX, asserting it held the authority to do so. IBM countered by affirming their license was "irrevocable" and continued distributing AIX unabated. SCO pursued an injunction aimed at stopping IBM’s sales and demanded either destruction or return of all AIX copies, grounding its request on alleged copyright violations stemming from IBM’s ongoing distribution.

Privately, Novell advised SCO that it believed SCO lacked the right to revoke IBM’s license. Novell referenced Section 4.16(b) of their Asset Purchase Agreement with SCO, which granted Novell the power to intervene and nullified SCO's termination rights.

Judge Kimball’s ruling on August 10, 2007 reaffirmed Novell as the rightful UNIX owner with authority to waive SCO’s attempt to terminate IBM’s license.

IBM's counterclaims against SCO

On August 6, 2003, IBM submitted its counterclaims against SCO comprising ten allegations including Breach of contract, violations of the Lanham Act, Unfair competition, intentional interference with prospective economic relations, unfair and deceptive trade practices, breach of the GNU General Public License, as well as four counts of patent infringement.

Initially, SCO contended that the GPL was unenforceable and unconstitutional but later withdrew this argument. Had this position prevailed, SCO’s ongoing distribution of GPL-licensed programs such as Samba would have been unlawful without approval from copyright holders.

On September 25, 2003, IBM expanded its counterclaims to thirteen by adding Copyright infringement—accusing SCO of infringing GPL-licensed IBM code within Linux—along with claims of Promissory estoppel and requests for Declaratory judgment. On March 29, 2004, IBM amended its filings again by dropping one patent infringement claim but including two declaratory judgments seeking rulings that IBM's use of AIX and Linux did not infringe any rights.

Discovery process

The discovery period extended over several years. SCO asserted that any software derived from SVRX, including AIX, was infringing since it alleged IBM contributed AIX code into Linux. Consequently, SCO sought access to AIX source code for comparison purposes; however, IBM denied that AIX was derivative work and requested SCO specify which Linux code allegedly infringed copyrights. SCO responded that it could not identify infringing Linux code without first examining the AIX source.

On December 5, 2003, a judge ruled in favor of IBM by ordering SCO to specify within 30 days the particular Linux code underpinning its claims—a notable procedural advantage for IBM.

On June 28, 2006, Judge Brooke Wells excluded most of SCO’s evidence due to failure to meet specificity standards established since December 2003:

SCO appealed seeking a de novo review. On November 29, 2006, Judge Dale Kimball fully upheld Judge Wells’ ruling.

Disputed code

During a reseller conference in August 2003, SCO presented a snippet of code they claimed had been copied, which was later identified as originally distributed under a BSD License.

This code segment, known as atealloc, had appeared briefly in the IA-64 Linux version but was removed on July 4, 2003, due to technical issues and because it was considered "extremely unattractive."

The UNIX pioneer Dennis Ritchie verified that either he or Ken Thompson authored the atealloc code, which is licensed under the BSD license. SCO is accused of stripping the original license statements from Unix source components (including the Berkeley packet filter), potentially breaching the terms of the BSD license.

Claims of copyright infringement and DMCA actions

In late December 2003, new developments emerged when Novell asserted their copyright ownership over the original UNIX source code, contesting SCO's copyright registration.

The SCO Group declared that it had issued DMCA takedown notices alleging unauthorized use of copyrighted material. These letters, made publicly available online, identified 65 files within the Linux source tree that were claimed to contain "copyrighted binary interfaces." Linus Torvalds issued a formal response on Groklaw disputing these allegations.