In a recent eWEEK story by ace operating system reporter Peter Galli, Microsoft Challenges Linuxs Legacy Claims, Bill Hilf, director of Microsofts Linux and open-source lab, claimed that the labs tests of Windows and Linux on legacy hardware found that when both were installed and run out-of-the-box, it "put to rest the myth that Linux can run on anything."
Hilfs point is that, of course, you can strip Linux down to run on an older system, but that the users who are most likely to run 1990s vintage equipment are the ones who are least likely to be able to set up Linux properly on antique hardware.
To prove his point, Hilf took full-scale server and desktop distributions like RHEL (Red Hat Enterprise Linux), SUSE Linux 9.3, Linspire 4.5, and Xandros 3, along with Microsofts own Windows XP and Server 2003, and tried to run them on older hardware.
To no ones surprise, he found that none of these will run on 1997-vintage hardware with a 233MHz Pentium, 32MBs of RAM, and a 2GB hard drive.
What Hilf didnt mention was that according to Microsofts own tests, Slackware 10.1 and Knoppix 3.7 do run on this hardware.
I might add that other modern Linux distributions, which are designed to run on low-end systems, work just fine on such PCs.