The first time I heard about hash tables was after taking a compilers course during my BSc. The truth is, I was not able to understand and appreciate their usefulness fully back then. Now that I know more about hash tables, I decided to write about them so others will see their importance as well.

For any object moving through a fluid, forces are applied to the object as the fluid moves around it. A fluid can be something like water, or even something like the air around us. When the object is specifically designed to maximize the forces that the fluid can apply, you can designate these designs as airfoils. A more common name that most people would use is a wing.

I don't know how many readers know this, but my very first Linux Journal column ("Browse the Web without a Trace", January 2008) was about how to set up and use Tor. Anonymity and privacy on the Internet certainly take on a different meaning in the modern era of privacy-invading software and general Internet surveillance.

Take on "dependency hell" with Docker containers, the lightweight and nimble cousin of VMs. Learn how Docker makes applications portable and isolated by packaging them in containers based on LXC technology.

Password authentication contains a lot of assumptions about security and trust. Encrypted SSH tunnels and public key verification are two common ways to ensure that your password is not compromised in transit. But, what if it's the computer you're currently typing on that can't be trusted?

The Minority Report has been in rotation on cable lately, and you've probably seen the futuristic vision of Tom Cruise standing in front of a large screen, manipulating information with waves of his hands. That vision is a bit closer to reality, thanks in part to the economies of scale of the game industry.

VirtualBox is a free, powerful and versatile virtualization program which is available for Linux, Mac, and Windows hosts, and can virtualize many different Operating Systems. VirtualBox was originally developed by Innotek, but was purchased by Sun and renamed Sun xVM VirtualBox.

As a consultant, I am often faced with an unfamiliar Linux system (usually RHEL). I always find it useful to understand which files that shipped with rpm packages have been modified, since it's usually a good indicator of what customizations have been performed on the system. To determine the modified files, I simply run:

Often, a kernel developer will try to reduce the size of an attack surface against Linux, even if it can't be closed entirely. It's generally a toss-up whether such a patch makes it into the kernel. Linus Torvalds always prefers security patches that really close a hole, rather than just give attackers a slightly harder time of it.