Anyone that uses System Center Operations Manager knows that the documentation is a bit sparse. This book more than makes up for that lack of information. The authors have created a very thorough and complete set of information starting with outlining the reason for SCOM and the underlying architecture. They spend a great deal of time and effort describing how to install and configure the tool. My favorite sections start about half way through when they get into configuring all the rules and monitors to gather data and respond to alerts. The chapter on reporting was also very helpful. They even include a small section on other management packs in the Appendixes, with information on the one that interests me most, SQL Server. The Appendix also has a great walkthrough on step by step configuring and tuning your own management pack.
I can't say this is a must own for anyone using SCOM, but if you've been floundering a bit, as I have, or you're just getting started, this is a fantastic resource to get you on your feet and get your SCOM system up and running. Review by: Grant Fritchey

Power supply (PSU) is the device that transfers electric power from a source to a load using electronic circuits. A typical application of power supplies is to convert utility's AC input power into regulated DC voltage(s) required for electronic equipment.
Depending on the mode of operation of power semiconductors PSU can be linear or switching (SMPS). What is SMPS? SMPS stands for switch mode power supply. In this supply power handling electronic components are continuously switching on and off with high frequency in order to provide the transfer of electric power via energy storage components (inductors and capacitors). By varying duty cycle, frequency or a relative phase of these transitions average value of output voltage or current is controlled . The frequency range of an SMPS is from 20 kHz to several MHz