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AARD code

The AARD code was a segment of code in a beta release of Microsoft Windows 3.1 that would issue a cryptic error message when run on the DR DOS operating system rather than the Microsoft-affiliated MS-DOS or PC DOS. Microsoft inserted the code in an attempt to manipulate people into not using competing operating systems; it is an example of the company's fear-uncertainty-doubt tactics.

Description

This XOR-encrypted, self-modifying, and deliberately obfuscated x86 assembly code used a variety of undocumented MS-DOS structures and functions to detect if a machine was running DR DOS. The code was present in the installer, in the WIN.COM file used to load Windows, and in several other EXE and COM files within Windows 3.1.

The AARD code was discovered by Geoff Chappell on 17 April 1992 and further analyzed and documented in a joint research effort with Andrew Schulman. The name "AARD code" came from the letters "AARD" that were found in a hex dump of the Windows 3.1 installer; this turned out to be the signature of Microsoft programmer Aaron R. Reynolds (1955–2008).

Microsoft disabled the AARD code for the final release of Windows 3.1, but did not remove it so it could be later reactivated by the change of a single byte.

DR DOS publisher Digital Research released a patch named "business update" in 1992 to bypass the AARD code.

Memos

The rationale for the AARD code came to light when internal memos were released during the United States v. Microsoft Corp. antitrust case in 1999. Internal memos released by Microsoft revealed that the specific focus of these tests was DR DOS. At one point, Microsoft CEO Bill Gates sent a memo to a number of employees that said, "You never sent me a response on the question of what things an app would do that would make it run with MSDOS and not run with DR-DOS. Is there [sic] feature they have that might get in our way?" Microsoft Senior Vice President Brad Silverberg later sent another memo, saying, "What the [user] is supposed to do is feel uncomfortable, and when he has bugs, suspect that the problem is dr-dos and then go out to buy ms-dos."

After Novell bought DR DOS and renamed it "Novell DOS", Microsoft Co-President Jim Allchin wrote in a memo, "If you're going to kill someone there isn't much reason to get all worked up about it and angry. Any discussions beforehand are a waste of time. We need to smile at Novell while we pull the trigger."

Lawsuit and settlement

Novell DOS changed hands again. The new owner, Caldera, Inc., began a lawsuit against Microsoft over the AARD code, Caldera v. Microsoft, which was later settled. It was originally believed that the settlement was around $150 million, but in November 2009, the settlement agreement was released, and the total was revealed to be $280 million.

See also

Further reading

  • (Details and initial discovery)
  • (Caldera v. Microsoft details)
  • (Site with email excerpts from Microsoft and an example of tripping the AARD code (XMS error))

References

  1. <ref name="Chappell_1999_AARD-1"> (Web article published by Geoff Chappell on 3 September 1999 about an e-mail sent to Andrew Schulman on 17 April 1992.) Record of AARD Research 2011-11-24, retrieved 2016-11-25^
  2. First Public AARD Details 2011-11-24^
  3. Examining the Windows AARD Detection Code - A serious message--and the code that produced it Dr. Dobb's Journal, Miller Freeman, Inc., September 1993, retrieved 2013-10-05^
  4. (xviii+856+vi pages, 3.5-inch floppy) Errata: Undocumented DOS: A programmer's guide to reserved MS-DOS functions and data structures - expanded to include MS-DOS 6, Novell DOS and Windows 3.1 Addison Wesley, 1994^
  5. Aaron R. Reynolds Seattle Times, 2008-08-04^
  6. Microsoft Plays Hardball Eat the State!, 1998-10-21, retrieved 2008-08-21^
  7. The Microsoft Monopoly Debates 2000-04-01, retrieved 2008-08-21^
  8. 25 years of DR DOS history - Digital Research DOS history FreeDOS.org, 2000-09-18, retrieved 2013-10-05^
  9. How MS played the incompatibility card against DR-DOS - Real bear-traps, and spurious errors The Register, 1999-11-05, retrieved 2013-09-26^
  10. Windows Warning Resurfaces in Suit Associated Press, 1998-08-28, retrieved 2016-11-25^
  11. In the United States District Court - District of Utah, Central Division - Caldera, Inc. vs. Microsoft Corporation - Consolidated statement of facts in support of its responses to motions for summary judgement by Microsoft Corporation - Case No. 2:96CV 0645B Caldera, Inc., April 1999, retrieved 2018-08-05^
  12. In the United States District Court - District of Utah, Central Division - Caldera, Inc. vs. Microsoft Corporation - Case No. 2:96CV 0645B - Caldera, Inc.'s Memorandum in opposition to defendant's motion for partial Summary Judgment on plaintiff's "Technological Tying" claim Caldera, Inc., May 1999, retrieved 2018-08-05^
  13. Caldera submits evidence to counter Microsoft's motions for partial summary judgment Caldera, Inc., 1999-04-28, retrieved 2018-08-05^
  14. In the United States District Court - District of Utah, Central Division - Caldera, Inc. vs. Microsoft Corporation - Case No. 2:96CV 0645B - First amended complaint and jury demand Tech Law Journal^
  15. Microsoft emails focus on DR-DOS threat CNET News, 1999-04-28, retrieved 2008-08-21^
  16. Caldera vs Microsoft - the settlement BBC News, 2000-01-13, retrieved 2008-08-21^
  17. Caldera settlement shows a new side of Microsoft cnet, 2000-01-11, retrieved 2009-01-19^
  18. Exhibits to Microsoft's Cross Motion for Summary Judgment in Novell WordPerfect Case Groklaw, 2009-11-23, retrieved 2011-10-22^
  19. Microsoft: Vorgetäuschter Bug legte DR-DOS lahm Heise Online, Verlag Heinz Heise, 1998-08-27, retrieved 2018-07-14^
  20. Microsoft's memorandum in opposition to Novell's renewed motion for summary judgement on Microsoft's affirmative defenses and in support of Microsoft's cross-motion for summary judgement 2009-11-13, retrieved 2018-08-03^
  21. (NB. This document of the Caldera v. Microsoft case was an exhibit in the Novell v. Microsoft and Comes v. Microsoft cases.) Settlement agreement - Microsoft Corporation and Caldera, Inc. reach agreement to settle antitrust lawsuit 2000-01-07, retrieved 2018-08-03^
  22. Microsoft Will Pay $275 Million To Settle Lawsuit From Caldera The Wall Street Journal, 2000-01-11, retrieved 2019-11-24^
  23. (NB. This court document is a copy of a mail by Aaron Reynolds written in 1991 and forwarded by one of its recipients, Phil Barrett, in 1993.) msdos detection - hot job for you 1993-02-24, retrieved 2018-08-04^
  24. Customers and Novell 1993-09-18, retrieved 2018-08-04^
  25. DR DOS 6.0 does Windows 3.1 Computerworld, 1992-04-20, retrieved 2019-07-22^