I recommend following link:
As few as 15 years ago, if you mentioned security to someone in the business world, they would immediately think about alarm systems, badge readers and door locks. Some years back, I visited the Equifax Atlanta data center, entry to which required a retina scan and practically an act of Congress. Today, the focus is on logical security — threat management, breach detection, intrusion prevention, etc. With the threats we face today from all over the world, logical security is very important. Physical security has unfortunately been relegated to the realm of secondary concerns…….