Dell has been a standard in the Intel based server market for many many years, and in the past, that generally meant that the OS provider for those systems was Microsoft. While Windows is still the OS for the majority of Dell servers sold, Dell now says that Linux makes up 25 percent of its enterprise market and that they see those numbers growing, not shrinking, over time. The increase in Linux sales is attributed primarily to Dell customers who have migrated from Unix based systems. For those customers, Linux is viewed as a comfortable change and isn't nearly as drastic as switching to a Windows based system.
Marching in tune with their increased Linux sales, Dell also states that they have improved their Linux services market and are capable of solving over 90 percent of Red Hat Linux service calls without involving Red Hat. Up to this point Dell has focused Linux sales primarily on the Red Hat distribution, but they are now in the process of approving Novell/SUSE Linux as a Tier 1 offering.
News source: ZDNet UK