For those of you who travel too much ... I'd like to introduce you to FlightMemory - it allows you to track all your trips and tells you total hours in the air, top airport, shows you a map of all your flights, etc.  Now you can really show your friends and family how much of a time consuming pain travel is!  (BTW, my six year old has got it down.  After three long flights in one day he decided that flying gives him a headache.)

Given all the interest in wind energy these days, and the fact that I live in a very windy area, I decided to start measuring wind speed and direction. I found some inexpensive, robust wind instruments, a cheap AVR microcontroller, and set out to build the firmware using an open source C compiler, WinAVR, based on the GNU gcc for Windows. I mounted the wind instruments on my garage and fed the signal to the AVR controller I have in my home office. The AVR microcontroller spits wind speed data out the serial port which is connected to the Linux box. That server turns the wind data into an XML file that's served by an Apache web server. I wrote an example Flash application which reads the XML and adjusts some graphical meters in near-real time (every 5 seconds.) I've released the project as Open Source under the Apache v2 license for the software I wrote. Take a look at OSCirrus.see-do.org for more details, schematics, sensor construction, and downloads of source code. Since I've put up the sensors, I've captured some huge and sustained gusts of wind. Here is a snapshot of the Flash-based GUI that shows the speed history during a severe wind storm that had gusts up to 60mph: So, dig in, have fun.

Background In this article, I'm going to take you on a quick tour for configuring virtual hosts on apache, but then leave you with the one tip that glues it all together. Normally if you're hosting a web site on Linux/Apache, your ISP is handling all this for you, but if you're like me and like to maintain various personal web sites that don't get a lot of traffic, you can put up a Linux box on your DSL connection and have all the disk space and freedom you want to manage your server and try out new technologies. Apache does a great job of hosting independent domains on the same instance through its virtual host capability. All domains can have the same IP address - Apache sorts it out based on the request URL and multiplexes the request to serve it from the correct document root/web site. Apache stands there as a traffic director giving the illusion that each site is completely independent despite they all live on the same server and use the same IP address. That's the basic model of shared web hosting, but you can use it for yourself to maintain your own server with multiple domains on the internet. How To Configure a Virtual Hosted Apache 2 Server If you haven't already, as root, create an /srv/www/vhosts directory # mkdir -p /srv/www/vhosts Then for each domain you want to host on the server, create another subdirectory under vhosts that contains the name of the domain. For example, I have a personal site called sawdust.see-do.org that I use to stash and document various technical projects I have on the side. I have another site I use to host an open-source project I started called OSCirrus.see-do.org (a wind measurement microcontroller, firmware, and instruments project.) With those two sites as an example, my /srv/www/vhosts directory will look like this: lcox@flash:/srv/www/vhosts> ls -l
total 2
drwxr-xr-x 18 lcox www 648 2007-05-03 18:25 oscirrus.see-do.org
drwxr-xr-x 14 lcox www 496 2007-05-18 08:34 sawdust.see-do.org
Depending upon who's going to be updating the site, you'll want to change the ownership of the site directories. In this case, I used my own user account, 'lcox', as the owner and 'www' as the group. Under these domain directories is the normal content you would see for a web site that lives under an Apache htdocs directory, for example. Now, over in your Apache config file, typically in /etc/apache2/httpd.conf you'll see what amounts to a template for virtual hosting in the form of an Include directive. If it's commented out ("#"), then uncomment this line: Include /etc/apache2/vhosts.d/*.conf Under the vhosts.d directory, you will create a configuration file for each of your domains; in this example, I created two .conf files...one for oscirrus.see-do.org and one for sawdust.see-do.org. Note, you don't need to match the file name with any domain in particular. That is the conf file name is arbitrary, but in practice it will reflect some part of the domain name it's describing. I created the files from a template Apache gives you called vhost.template which lives in the same directory:

lcox@flash:/etc/apache2/vhosts.d> ls -l
-rw-r--r-- 1 root root 4203 2007-04-12 19:46 oscirrus.see-do.conf
-rw-r--r-- 1 root root 4196 2007-04-11 20:31 sawdust.see-do.conf
drwxr-xr-x 2 root root 48 2007-03-17 19:41 vhosts
-rw-r--r-- 1 root root 9147 2005-09-09 15:33 vhost-ssl.template
-rw-r--r-- 1 root root 4237 2005-09-09 15:33 vhost.template
So, just do a: # cp vhost.template mydomaingoeshere.conf for example, to get a virtual host configuration for your domain. Inside that conf file is nothing special, but you will need to change the various Apache directives to reflect your domain specific names and locations for things like access and error logs, the server name, admin email, etc. These are all exactly like the normal Apache directives of a non-virtual domain, so nothing special needs to be noted. The critical directive to change will be the ServerName - for example: ServerName oscirrus.see-do.org In order for your new changes to take effect, you need to restart Apache which takes just a few seconds. A typical way to do this is: # /etc/init.d/apache2 restart Domain Registration Assuming you have registered your domains at a registrar such as Network Solutions, DirectNIC, GoDaddy (or any number of the others out there), you will need to login to your registrar account and point the domain to a DNS server. I use ZoneEdit for DNS services because I can very easily repoint a domain or subdomain to a new server and the changes take effect almost instantaneously without having to repoint my domain at the registrar. So, all my domains at my registrar point to DNS servers at ZoneEdit and then at ZoneEdit, I resolve the domain's address to the IP of my server that's behind my DSL connection. So, if you haven't already set up your domain registration and DNS, you'll need to do that before any of this can begin to work and insure you can reach your server from elsewhere on the internet. I won't cover how to do all this since DNS procedures are really well documented and there a 1,000 ways to do it. Finally, Here's the Glue Tip Everything above is pretty self explanatory, well-trodden territory, and the Apache files do a great job of leading you to the virtual host water. You can do all that correctly and still hit this one nasty problem. If you have multiple virtual hosts and you try to request a URL from the 2nd or 3rd host, for example, you'll always get the page from the first virtual host - a maddening state of affairs. So, here's the one line of glue code that's not included in the typical Apache conf template that makes it all work. Over in the /etc/apache2/httpd.conf file, immediately above the Include directive for the vhosts.d conf files, you need to add a line: NameVirtualHost *:80 In context it will look like this: # this NameVirtualHost is critical otherwise any virtual host request will only
# resolve to the first one
NameVirtualHost *:80
Include /etc/apache2/vhosts.d/*.conf
Summary There are lots of tutorials on the net for setting up virtual hosts, but none that I found cover that one magic line - you'd have to dig it out of google/forum posts or somewhere else. So, hopefully, this a) spurs you on to try virtual hosting on Apache and b) saves you a bunch of time trying to figure out how to make it work.

When I first read the Microsoft saber rattling article in Forbes a week ago where Microsoft claimed open source projects including Linux, OpenOffice and others violated 235 of Microsoft's patents, my first thought was: "Is that all?" Out of the millions of lines of code those open source projects represent, the idea that they allegedly violated 235 patents is absolutely amazing considering there are patents granted on the most mundane things like transferring data from one computer to another over a network. I would have thought the number of violated patents was much, much higher. If Microsoft would have made the claim that open source projects violated exactly 8,154 patents, I would have believed it. Imagine trying to commute to work in a Tokyo subway and not rub up against anyone else or step on a foot. That's the visual picture of the patent landscape today. Given how loosely and freely the patent office hands out its goods, it's not an exaggeration to say it's impossible now to create a product without violating a patent somewhere. The question isn't whether a patent is violated when new software is developed, the only question left is whether a patent holder somewhere will press its case. If your product is successful, it's a given you'll have to defend. Microsoft might be the poster child of frivolous patents, but recently when Steve Jobs announced the iPhone and claimed their development resulted in over 500 patents (applied for or awarded, I don't know the exact details), he was bragging about how innovative they were, but it's truly a sad day when one device can lay that much claim in the intellectual land grab game that's been going on for the last 15 or 20 years in technology. The iPhone will be a distant footnote in technology history by the time its patents expire. To be sure, Microsoft must see patents as a double-edged sword. No doubt, frivolous patents have been used to extract money from the company. So, in some ways I can't blame them for puffing up their patent portfolio for defensive purposes, but the threshold they're using to activate those defenses seems to be lowering day-by-day. Either they're getting weaker, feel more vulnerable, or open source is getting stronger for these kinds of PR skirmishes to be breaking out into the open.

Working on documentation at OpenLogic, I spend a lot time looking at release notes. When a new version of a project we support is released, I need to find out what will be most important and useful for our customers to know about it. Whether I'm trying to find the latest security patch or just looking for the highlights of the new version, some release notes are much easier to view and work with than others. 

Finding the Release Notes