Windows in charge of Linux execution?

But then you knew that.

There wasn't a Groklaw back then, but there was Dr. Dobbs. The legwork's now 13 years old. Read it your self in Andrew Schulman's Examining the Windows AARD Detection Code: A serious message--and the code that produced it. This concerns a bit of code, "AARD", heavily obfuscated and encrypted, included in a beta release of Windows 3.1 which produced a warning message when run on DR DOS, though the condition it tested appeared to have no impact on any Win3.1 functionality.

The AARD code has no relation to the actual purpose of the five otherwise-unrelated programs into which it has been dropped. It appears to be a wholly arbitrary test, a gratuitous gatekeeper seemingly with no purpose other than to smoke out non-Microsoft versions of DOS, tagging them with an appropriately vague "error" message.

Schulman goes on to discuss Microsoft's response to his inquiries, and possible motives:

I've presented the substance of these findings to Microsoft, at both engineering and management levels. At press time, a detailed response was not forthcoming, perhaps due to the ongoing FTC investigation. It's likely that a subsequent issue of DDJ will contain a more specific response. However, a high-level manager at Microsoft repeatedly told me that the company is "agnostic" regarding DR DOS. He added, "They [Novell] claim 100 percent compatibility, but DR DOS is full of bugs. If DR DOS has problems running Windows, Novell should fix them."

The implication is that if a Windows/DR DOS user gets an error message that a Windows/MS-DOS user doesn't, then by definition it is Novell's fault and proof that DR DOS isn't "100 percent DOS compatible." The problem with this is that, as Figure 5 shows, the AARD code's test for DOS compatibility is 100 percent artificial. By Microsoft's definition, only MS-DOS or something byte-for-byte identical with MS-DOS (and therefore in violation of copyright) is "100 percent DOS compatible."

As for "agnostic," this seems unlikely given the effort required to write this tricky code. Its presence in five otherwise-unrelated programs also suggests a fairly concerted effort, as it is unlikely that five so different programs are all maintained by the same person. In fact, the programs probably fall under the domain of several different product managers or divisions.

I very strongly recommend reading the entire article.