Re: Microsoft's OS competitors

On 4/23/97, Mark Lemley wrote:
>
> Why haven't any potential Microsoft competitors reverse-engineered
> its operating system, copied the necessary functional components,
> and built a competing "Windows-compatible" operating system?

I suspect the answer is mostly your #4 (because it's hard), with a dose of FUD about having to litigate against Microsoft re your numbers 1-3 (copyright, patent, trade secret), even if Microsoft eventually lost on the merits.

Novell and IBM both attempted to sell alternatives to MS-DOS, circa 1991 (or so). If I remember correctly, Novell's version (DR-DOS) was more or less a rewrite of DOS which complied with the available specs, while IBM's version was based upon an older version of MS-DOS which IBM had a license to modify/resell.

Neither product was a success in the marketplace - I'd be suprised if they even gained 2% of the market (together) against MS-DOS. It's my impression that their failure was a result of tiny inconsistencies with MS-DOS, consumer fear that there would be a significant and hidden inconsistency or incompatibility, and aggressive sales practices on Microsoft's part. In particular, I suspect many people avoided DR-DOS and IBM DOS because they were concerned about performance/compatibility while running Windows (back in the days when DOS and Windows were separate products).

Reverse-engineering DOS or Windows is harder than it might sound, because they've got hidden and undocumented features. See, e.g., _Undocumented DOS_ by Andrew Schulman; there are more books along these lines, but I stopped paying attention when I switched careers and went to law school.

An example of rewriting an operating system (with slightly different parameters) is Linux, a rewrite of the Unix operating system. In contrast to Windows/DOS, Unix is pretty well understood and welldocumented,  and the source code has been freely available (but not freely redistributable) for quite some time. (Its owners are/have been, for the most part, the University of California and AT&T.) The Linux rewrite has flourished, spawning a cottage industry of software and hardware vendors who offer inexpensive products for Linux systems. (Linux runs mostly on PC hardware but has been ported to other platforms.) Linux even features a "Windows emulator", although I suspect that the complexity of running a Unix system scares off most people who'd otherwise be interested in that.

My hunch is that if someone did come up with a copyright-clean version of Windows (I don't think there are any strong patent/trade secret claims), Microsoft would litigate aggressively (costing the authors of the alternate version lots of time/$) .. and if the product made it to market, Microsoft would drop their Windows prices long enough to kill off the competitor. Microsoft is a formidable opponent - most software companies can probably find some lower-hanging fruit to pick.

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