In January, 1998, Fermilab announced that Linux would be one of the officially supported operating systems at the lab. Several restrictions apply to this policy, the most important being that only distribution and hardware platform supported are Fermi Linux on Intel PC's. A short but comprehensive document was issued which is available online. 

In light of a change in support policy, we had to revise our support policy. This new support policy was initially drafted in November 2003. Read it here.