&lt;p&gt;Managers of data centers offering collocation and cloud services sign contracts guaranteeing 100% up-time. Most engineering types would say that's impossible; however, that kind of guarantee is the cost of doing business in today's market. If the service is anything less than 100%, clients get substantive refunds, and the data center loses credibility.&lt;/p&gt;&lt;p&gt;That could explain why data-center operators will spend millions of dollars on backup power-generation equipment, which more often than not amounts to diesel generator sets similar to the&lt;span&gt; &lt;/span&gt;Cummins&lt;span&gt; &lt;/span&gt;model pictured above.&lt;/p&gt;&lt;p&gt;To learn more about how these monsters work, I contacted the&lt;span&gt; &lt;/span&gt;Cummings Power-Generation Business Unit, which is the division that builds generator sets of all sizes, from Oman RV models on up. At the division headquarters in Minnesota I met Richard Hallahan, Technical Marketing Manager for Data Centers and a certified professional engineer, and he ushered me into a high-tech conference room and asked how he could help.&lt;/p&gt;