The cloud. Mega data centers. Security breaches. 2013 was chock full of interesting data center developments. What were the most popular stories at Mission Critical based on page views, most emailed, and downloaded? Read on.

5. Smoke Detection Requirements In Data Centers. Smoke and fire detection in data centers is an extremely important endeavor. Not only is it an issue of protecting expensive data center equipment, downtime can mean the loss of serious money. This article, written by Phil Mazzurco of Siemens, discusses recent code changes and ways to protect your investment, and appeared in the July/August 2013 issue.

4. Year Long Road Trip Part IV: Selecting a collocation/wholesale data center provider. “Target: TCO” debuted in the January/February  2013 issue of Mission Critical. Written by Paul Schlattman, vice president of the Mission Critical Facilities Group at ESD, the column unfolded throughout the year as a six-part look at the “steps required to getting to a total cost of ownership (TCO) when building or selecting a new data center.” Part four, which appeared in the July/August issue, hit on another hot topic in 2013: collocation.

3. Data Center Site Selection Based on Economic Modeling. Debra Vieira, a senior electrical engineer at CH2M Hill, wrote this article for the January/February issue. In it Vieira discusses how economic modeling is being used more and more for site selection and how owners can leverage the process for their own projects.

2. Choosing between transformer free and transformer based UPS designs. Power is, and continues to be, one of the hottest topics in the data center world. Bill Campbell, senior product manager with AC Power Systems, Emerson Network Power, discusses the current debate between the two technologies and how to choose the best type for your application in the January/February issue of Mission Critical.

1. The Advent of the Tier 5 Data Center. In the January/February issue, Mission Critical columnist Julius Neudorfer discusses how virtualization will change “the boundaries and reference points of availability tiers” and what that can mean for data center operators and the data center of the future.