One of the more commonly overlooked items when creating shell scripts is their ability to do more than just output to the command line. The misconception that a well written script cannot create or display more advanced GUI controls (progress bars, warning boxes, status updates, etc) will be addressed in some detail. We are going to look at several ways that you can use your shell scripts in a more user friendly manner.
The SpaceX Dragon launches March 1, 2013 at 10:10am EST, are you ready? For the past few of weeks we’ve been breaking down key systems of the Falcon 9 and Dragon to get you prepped for the SpaceX CRS-2 Commercial Resupply Services flight.
Here’s what you missed—
Short for Laser Imaging Detection and Ranging, LIDAR is used for a variety of mapping, distance and speed measuring tasks. It is a key feature in unmanned vehicles, like the SpaceX Dragon spacecraft. SpaceX and NASA worked with Advanced Scientific Concepts (ASC) to design DragonEye, the 3D Flash LIDAR Space Camera developed for the Dragon.
While a DragonEye LIDAR sounds like a subplot to a James Bond movie, it is what the Dragon spacecraft uses to approach and position itself to dock with the International Space Station. Laser precision comes in handy when trying to attach the 1.3-meter hatch of the Dragon to the football-field-sized space station which travels at an astounding speed of 4.71 miles per second. Once the Dragon capsule passes the R-Bar, it has to preform a series of staggered maneuvers to gradually approach the ISS Keep out Zone, a 200-meter border around the ISS, and get ready for the Canada Arm to grab it at 10-meters out.
As anyone who has worked in the Open Source World for some time, I have stocked my toolbox with a large number of common programs and utilities that help get the job done. All major distributions have each of the tools I am going to talk about either installed by default during setup or available via their core repositories post installation.
These tools will provide us the information and metrics to not only see what is going on with our system but will help with the analysis necessary when performance or stability becomes an issue. We are going to look at the ‘Top’ tools for finding disk, CPU, network and/or other system bottlenecks as well as some that just answer some basic questions. By no means is this initial list anywhere near comprehensive. I intend to follow up this article with several others introducing other tools and eventually diving in deeper with the more complex applications.
Elon Musk is no stranger to media coverage, but the media covers him quite strangely. He is most often labeled as a billionaire, secondly as an entrepreneur, and thirdly by his corporate titles. While those labels are factually correct they don’t seem accurate.
Elon Musk is a billionaire but lives like a starving artist. You might be thinking I’m on some serious drugs because you know he just bought a $17 million home and has a private jet among other amenities. So where does my starving artist label come in? It’s in the way he uses his money and, life’s most valuable resource, time. It starts after his PayPal days. With millions of dollars in hand, he could have invested it and lived a nicer life than most of us will ever know. Instead he celebrated the PayPal sale by buying some nice things and used most of his remaining net worth, not to start another internet company that would’ve likely been successful but, to start SpaceX a venture he thought would likely fail. The source of his motivations are not monetary they stem from a desire to create, to develop an idea that does not yet exist, and he does so whether or not people understand him. Much like an artist, he invests most his time and money bringing his ideas to life except his canvas is humanity, his paintbrush is physics, and his color palette is technology.
One of the most common areas in Linux that gets overlooked during a production deployment is overall security. Specifically, the hardening of the operating system against common exploits (and hardening can encompass both policy and configuration for both internal and external use). We are going to talk about some common ways to protect our server from both the inexperienced as well as the malicious users it will be exposed to.
The thruster we will see in action on SpaceX’s next launch on March 1st will be the Draco. The Draco thruster is the smallest engine in the SpaceX fleet but don’t let the size fool you, it packs 90 pounds (400 N) of thrust. The Draco is a liquid propellant thruster that uses Monomethyl Hydranzine. There is an oxidizer needed with a liquid rocket engine and SpaceX uses Nitrogen Tetroxide, the combination of orbital propellant and oxidizer that were used for the Space Shuttle.
SpaceX went with a liquid fuel rocket because, while the thruster design is more complex, the advantage is variable thrust meaning the amount of fuel and the fuel burn rate can change during flight. Liquid fuel rocket engines can not only be throttled but are able to shut down and be restarted. Having so many options for throttle and restart are helpful in a redundancy situation. It also aides in maneuvering the precise approach required for to berth with the International Space Station (ISS). The combination of the propellant and the oxidizer keeps the fuel stable allowing the Dragon capsule to be berthed to the ISS for up to a year, providing a life boat of sorts for our cosmonauts.
The netstat command gives you a set of tools to answer the question “What in blazes is going on on my network?” when things go wrong. To be able to use it effectively at such an occasion, however, you might want to learn how it works right now, so you’ll be prepared. Besides, it never hurts to understand your network just a little better. Read on to find out exactly what netstat is, what you can use it for and how it can help you solve problems and understand your network.
A bundle of network tools
The netstat command doesn’t really do unique things. It can print network statistics, but ifconfig can do so, too. It can print routing tables, but route can do that, too. It can print open connections, but lsof does that, and more. So why use netstat at all? There are two main reasons:
- netstat bundles a few often-used network analysis actions in a single command and
- netstat is multi-platform.
There are several ways to end up with a satisfactory experience on the desktop with Ubuntu despite their recent confusion of the user interface. We will discuss some of those another day (KDE vs. Gnome vs. Cinammon vs. Unity). Today we are going to talk about setting up your desktop environment for multiple monitors. This article assumes you are running Ubuntu 12.04 LTS or 12.10, however, the process should work equally well back to version 10.04 LTS unless otherwise noted.
Assuming you have installed Ubuntu and are successfully sitting at the desktop (the window manager at this point is irrelevant), a couple of questions will now come to mind. What am I going to be using my linux desktop environment for? If you are going to be running office applications, email, basic web browsing and the occassional movie, you might be done. The default (read: Open Source) binary video drivers for both AMD (radeon) and Nvidia (nouveaux) are perfectly acceptable for all of those things. In fact, recently, they both have picked up some compositing support (so you can run the nifty 3D window effects in Compiz or KWin) as well as support for gaming. However, that support is spotty and performance still leaves a lot to be desired.
With the increases in bandwidth available to everyone, rich media services, and available information via the internet, video streaming is going to explode. You might think you see streaming everywhere now, but in realty video streaming is still in its infancy. There are many options for video streaming such as YouTube (yes, they have live streaming), Livestream, Ustream, and I’m sure there are a few others. However, some of those are expensive and others we just don’t want to use because of their branding. So what is the solution? Wowza! Seriously, the name is Wowza and we just happen to know a few experts that are going to help teach you to get started streaming with Wowza.