Thermal Management Techniques for VME Systems

The VMEbus specification, when first introduced in the early 1980s, allowed for power dissipation of about 35 watts per card, depending upon ambient temperature. Throughout the 1990s, the trend has been toward packag-ing more compute power, I/O and storage functions per card cage slot. Indeed, device technology has ad-vanced to give us lower power implementation of functions that would not have been possible 10 years ago. This document details techniques for thermal management in VME systems. Topics we will cover include different VME rack cooling methods and their effectiveness, temperature measurement, power distribution, and maximizing air flow.