End-user adoption of Linux servers for enterprise workloads, hosting ISV applications and databases, is on the rise, fueling a transition in the marketplace. The annual growth rate of Linux server unit shipments has been increasing over the past three years from 15% in 2Q01 to 40% in Q2 2004. Given this rapid adoption, the mix of form-factors for these Linux servers has been changing over time, with the result that dual-processor systems are the predominant form-factor, followed by uniprocessors and four-processor systems. A new IDC Insight study provides data about this trend, and shows the market dynamics, by form-factor segment, within the Linux server market space.Linux represents about half of the worldwide server blade market, in terms of unit shipments, compared to 20% of all rack-optimized servers and compared to 11% of all pedestal (standalone) servers. Between 1998 and 2003, the 1-way (uniprocessor) segment of the Linux server market grew at a healthy pace, with a 37.5% compound annual growth rate (CAGR). Growing at a CAGR of 89.8% from 1998 to 2003, dual-processor systems account for fully 74% of total Linux server shipment volume in the market today. Worldwide Linux server customer revenue is expected to reach $9.1 bln in 2008, driven by a CAGR of 22.8%, compared to the broad market CAGR of 3.8% for the worldwide server market. IDC forecasts that Linux server shipments will be 25.7% of worldwide server shipments in 2008, up from 15.6% of worldwide server shipments in 2003.