Aaron R. Reynolds
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The AARD code was a segment of code in a
beta release The software release life cycle is the process of developing, testing, and distributing a software product (e.g., an operating system). It typically consists of several stages, such as pre-alpha, alpha, beta, and release candidate, before the fi ...
of
Microsoft Microsoft Corporation is an American multinational corporation and technology company, technology conglomerate headquartered in Redmond, Washington. Founded in 1975, the company became influential in the History of personal computers#The ear ...
Windows 3.1 Windows 3.1 is a major release of Microsoft Windows. It was released to manufacturing on April 6, 1992, as a successor to Windows 3.0. Like its predecessors, the Windows 3.1 series run as a shell on top of MS-DOS; it was the last Windows 1 ...
that would issue a cryptic error message when run on the
DR DOS DR-DOS is a disk operating system for IBM PC compatibles, originally developed by Gary A. Kildall's Digital Research, Inc. and derived from Concurrent PC DOS 6.0, which was an advanced successor of CP/M-86. Upon its introduction in 1988, ...
operating system rather than the Microsoft-affiliated
MS-DOS MS-DOS ( ; acronym for Microsoft Disk Operating System, also known as Microsoft DOS) is an operating system for x86-based personal computers mostly developed by Microsoft. Collectively, MS-DOS, its rebranding as IBM PC DOS, and a few op ...
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 WIN.COM is the executable file used to load versions of Windows that run from DOS. In Windows 3.11 and its predecessors, it is executed either manually from the DOS prompt or as a line in AUTOEXEC.BAT. In Windows 95 and onward it is automatical ...
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 In computing, a hex dump is a textual hexadecimal view (on screen or paper) of computer data, from memory or from a computer file or storage device. Use of a hex dump of data is usually done in the context of either debugging, reverse engineer ...
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 Digital Research, Inc. (DR or DRI) was a privately held American software company created by Gary Kildall to market and develop his CP/M operating system and related 8-bit, 16-bit and 32-bit systems like MP/M, Concurrent DOS, FlexOS, Multiuser ...
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. ''United States of America v. Microsoft Corporation'', 253 F.3d 34 (D.C. Cir. 2001), was a landmark American antitrust law case at the United States Court of Appeals for the District of Columbia Circuit. The U.S. government accused Microsoft of ...
'' antitrust case in 1999. Internal memos released by Microsoft revealed that the specific focus of these tests was
DR DOS DR-DOS is a disk operating system for IBM PC compatibles, originally developed by Gary A. Kildall's Digital Research, Inc. and derived from Concurrent PC DOS 6.0, which was an advanced successor of CP/M-86. Upon its introduction in 1988, ...
. At one point, Microsoft CEO
Bill Gates William Henry Gates III (born October 28, 1955) is an American businessman and philanthropist. A pioneer of the microcomputer revolution of the 1970s and 1980s, he co-founded the software company Microsoft in 1975 with his childhood friend ...
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 feature they have that might get in our way?" Microsoft Senior Vice President
Brad Silverberg Brad Silverberg is an American computer scientist and businessman, most noted for his work at Microsoft in 1990–1999 as Senior VP and product manager for MS-DOS, Windows, Internet Explorer, and Office. He was named ''PC Magazine''s Person of th ...
later sent another memo, saying, "What the seris 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 Novell, Inc. () was an American software and services company headquartered in Provo, Utah, that existed from 1980 until 2014. Its most significant product was the multi-platform network operating system known as NetWare. Novell technolog ...
bought DR DOS and renamed it "Novell DOS", Microsoft Co-President
Jim Allchin James Edward Allchin (born 1951, Grand Rapids, Michigan, United States) is an American computer scientist, philanthropist and guitarist best known for being a former Microsoft executive. He assisted Microsoft in creating many of the system plat ...
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 Microsoft has been involved in numerous high-profile legal matters that involved litigation over the history of the company, including cases against the United States, the European Union, and competitors. Governmental In its 2008 annual report, ...
'', 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

*
Bug compatibility Computer hardware or software is said to be bug compatible if it exactly replicates an undesirable feature of a previous version. The phrase is found in the Jargon File. An aspect of maintaining backward compatibility with an older system is tha ...
*
Fear, uncertainty, and doubt Fear, uncertainty, and doubt (FUD) is a manipulative propaganda tactic used in technology sales, marketing, public relations, politics, polling, and cults. FUD is generally a strategy to influence perception by disseminating negative and dubio ...
(FUD) *
Halloween documents The Halloween documents comprise a series of confidential Microsoft memoranda on potential strategies relating to free software, open-source software, and to Linux in particular, and a series of media responses to these memoranda. Both the leaked ...


Footnotes


References


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)) {{DEFAULTSORT:Aard Code Windows components Microsoft criticisms and controversies