When I was setting up my server, I was faced with the problem of configuring subdomains to work with a dynamic DNS service such as DynDNS or No-IP. I recently had a user on the Ubuntu Forums ask me how I ended up getting things to work, so I wrote this article to explain.

My server used to have a 16GB hard drive and did not receive regular automated backups. I wanted to upgrade the drive to an 80GB one and use the old drive for automatic backups. This switch required that I somehow move the entire server installation from the old to the new, larger drive. So I decided to use a tool called Clonezilla. I cloned the old drive onto the new drive and set the new drive to the master. Booting up with the new drive worked fine. I put in the old drive (which still had the server installation) as a slave for backups. It was then that I ran into an interesting problem: no matter what I did, the old drive would always boot instead of the new one. After some probing, I found out that GRUB was run on the new drive, but it always pointed to the old drive. After about 6 hours of banging my head against the wall, I finally figured out that the UUIDs for the two drives were the same since they were cloned. Instead of using the generic (hd0,0), the Ubuntu distribution uses UUIDs by default to point to the drive that should be booted from. The UUIDs were not so universally unique anymore, and GRUB got confused and booted the old drive. So I guess the moral of the story is always make sure you change the UUIDs whenever a cloned drive is used. Anyways, sorry if this notice came too late. I hadn’t expected to run into such trouble.

So you know how to install Microsoft Office, upgrade drivers, and maybe even do a little overclocking or programming here and there. But have you ever wanted to know more about a computer - how it really works? Here are just a few ways that you can learn a bit more about the mysterious machine.

Just hours ago, Wolfram|Alpha was launched. If you have not been there already, check it out! This revolutionary site was just too exciting for me not to write about it. Wolfram|Alpha essentially makes libraries and libraries of knowledge available at a click of a mouse. Wolfram|Alpha is not a search engine, it is completely different and unique. You won’t know it until you try it. This definitely won’t replace Google for me, since the two products solve two different issues. Nonetheless, it will definitely be useful for school stuff. I’m not sure if it has much appeal for the normal Internet users, though.

Enabling searching in Drupal is easy enough, but a lot of people have trouble enabling the advanced searching capabilities in Drupal. Once an administrator enables a search box, they will be able to access the advanced search form on the search page. The problem, however, is that normal and unregistered visitors cannot see it.

When I started getting interested in electrolysis, I faced the problem of finding a power supply suitable for the high currents required. At first I was using wall-warts that could only supply an amp or so. My electrolysis units started consuming more and more current, so I burnt out about three of those. I then decided it was time for me to get a better power supply. I had heard of many people using car batteries, but while those can supply a lot of current, they are expensive and cumbersome to charge. If you do use a car battery for electrolysis, you basically have to get a deep-cycle one to prevent damage when it is drained. I also searched for bench power supplies meant for electronics, but those were too expensive and did not provide enough amps. Bench power supplies are very regulated, which isn’t that much of a deal when you aren’t dealing with sensitive electronics. I finally stumbled upon a solution that would satisfy all my needs: a computer power supply.

When recently upgrading my server to Ubuntu 9.04, phpMyAdmin was also upgraded to version 5.0.75. When I loaded up the new version, I was alarmed to find a new error message that read:

Normally when I open a book that explains how computers work, I get little illustrations of the CPU, RAM, hard drive, and graphics chip. This is a great way to educate people about computers, but I have always wondered how computers really worked - from the transistor up.