Loon Blog

There is a lot of buzz about “virtualization” these days, typically in the context of discussions concerning huge server farms. Virtualization can refer to many different things- the Wikipedia Entry offers a nice summary. It’s by no means a new concept and provides benefits at all scales, right down to the personal machine you’re using to read this blog.

The basic idea of a virtual resource- a virtual web server, virtual memory, a virtual machine- is that you use your existing hardware and software resources to create a new resource that you need. In a typical operating system, space on a disk drive is used to create the illusion that the system has more memory- virtual memory. On my web server, a single installation of apache software is home to six or seven different websites- virtual web servers. If you host your website and email with a provider like Cruzio, chances are that your “host” is a virtual machine on a server that is running a dozen or more virtual machines quite similar to yours. Kind of like the Matrix…

OK, so why do this? In the case of virtual memory it’s fairly obvious- we want to be able to have a whole bunch of applications running more or less simultaneously on our machines, and each of those apps wants memory. Fire up enough of them and eventually even your laptop with 4 GB of RAM needs to resort to using space on your disk drive to provide virtual memory. How about virtual web servers? Having a single, centrally maintained apache process that provides multiple virtual web servers allows me to share many common configuration settings and resources across all my servers while still letting me fully customize each web site. In the case of ISPs, virtual machines are a way for ISP’s to give their customers a “machine of their own” without having to install new hardware in a rack, and give it power, and a network connection, and air conditioning and so on. In this case virtualization can be a huge money saver and a fairly sound green strategy.

So, why am I particularly happy about virtualization recently?

I love my Ubuntu-based laptop. When I first got the laptop I immediately installed Ubuntu Linux alongside of Windows in a dual boot configuration. I figured I would occasionally need to boot windows for something. Well, it turns out that just about the only thing I find I need to boot Windows for is Adobe DreamWeaver, and I use DreamWeaver alot. Even if booting Windows were quick, that few minutes it takes to change environments can prove to be a real momentum killer.

A while back I had installed VirtualBox, a program that allows you to run virtual PC’s on your computer, to experiment with various Linux distributions. Once VirtualBox is installed, you use its control panel to create virtual machines, then install the operating systems on them from CD or whatever, almost exactly as you would with real machines. The installed OS’s are called “Guests”. Last week while I was waiting for Windows to boot so that I could run DreamWeaver, I decided I should try Windows Vista as a VirtualBox guest. I installed it from CD and it’s been working like a charm. I deactivated my “real” copy of DreamWeaver, installed and activated it on my “virtual” Windows laptop. Now when I need DreamWeaver I start my virtual Vista laptop, fire up DreamWeaver on it and do what I need. When I’m done I use the VirtualBox control panel to pause my virtual Windows machine. If I need it again I just resume it. I haven’t had to reboot to change operating systems since, which makes me (virtually?) happy.

If there’s virtually anything that Loon Systems can do for you- whether it’s fine tuning the virtual memory settings on your database server’s kernel to optimize performance, creating multiple virtual machines to support both your development and production environments, or setting up your web host to support multiple virtual servers- we’d enjoy hearing from you.

-Arch

If you’ve done any amount of web surfing you’re familiar with CAPTCHA’s, even if you didn’t know that’s what they’re called. According the the wikipedia entry, “CAPTCHA” is a contrived acronym for “Completely Automated Public Turing test to tell Computers and Humans Apart.”

How can a program distinguish computers from humans? By presenting an image of one or more words that are somehow visually scrambled, and asking the user (be it a person or a computer) to enter the words in a box. The idea is that even a computer able to recognize words in an image would not be able to interpret the scrambled image.

Why might you want to use a CAPTCHA on a web page of yours? Let’s say your business is recruiting for an open position. A web form is one tool frequently used to gather information about potential employees, but there is an ever-growing number of “bots” that prowl the web attempting to exploit just the kind of web forms you’d like to use. A CAPTCHA is just the ticket for ensuring that the information your form gathers comes from the human beings that you’d like to hear from.

OK- so where’s the good for humanity part? Enter reCAPTCHA. The “scrambled” words that reCAPTCHA uses are actual, inconclusive OCR (Optical Character Recognition) scans, so computer programs have already failed to unscramble them! Pretty neat, right? It gets neater. These failed scans come from an effort that is currently digitizing back issues of the New York Times. Each pair of words presented by the CAPTCHA contains one word whose unscrambled value is known to the CAPTCHA because a concensus-derived value for the word has been determined by presenting it to a large number of humans. The value of the second scrambled word is not yet known to the CAPTCHA, but you and other humans help unscramble it. When that happens the unscrambled value gets sent back to the people digitizing the NYT, bringing the digitized archive one word closer to completion. Check out the demonstration at reCAPTCHA.net

If you’d like Loon Systems to implement a CAPTCHA on your website, please drop us a line

-Arch.

Whenever you successfully get online, You’re witnessing multiple technologies working in harmony.

This blog post is made using WordPress which in turn uses php and MySql and of course displays everything in html and sends it via http from my server to your browser. If you’re viewing this post on the Loon Systems site, the site is managed using Adobe DreamWeaver CS3 and the blog post is embedded in the “latest blog posting” page using an iframe. And there’s so much more going on- css and google analytics and somewhere a server running apache…

You jaded techies out there thinking, “yeah, so what?” should take a second to appreciate just how marvelous the harmony is.

Our swiss army knives have become very thick indeed

-Arch.

The other day I was working on an OpenOffice spreadsheet to track the production of my Solar Electric system, creating a fairly straightforward “IF” statement. No matter how I tried, the cell yielded an Err:508, indicating a mismatch of parentheses or some other character. Naturally my first recourse was to turn to the online documentation which just confirmed that what I was doing should work just fine.

Enter the internet at large. Googling “Err:508 OpenOffice Calc” led me to a nugget indicating that (wait for it…) the documentation is WRONG! The docs say you can do:

=IF(Condition;True Value;Else Value)

but the fact of the matter is that in OpenOffice 3 the separator for the if statement is comma, NOT semicolon.

I live and I learn!

-Arch

Welcome to Loon Systems. Loon offers consulting services to help people live in harmony with technology.

Join us as we share our experiences. Hopefully you’ll find them amusing and informative. If you’d like to work with us, please visit the Loon Consulting Website

-Arch