computing

Why build a Raspberry Pi Cluster?

Raspberry Pi Cluster next to a banana for scale

After I posted my Raspberry Pi Blade server video last week, lots of commenters asked what you'd do with a Pi cluster. Many asked out of curiosity, while others seemed to shudder at the very idea of a Pi cluster, because obviously a cheap PC would perform better... right?

Before we go any further, I'd say probably 90 percent of my readers shouldn't build a Pi cluster.

But some of you should. Why?

Well, the first thing I have to clear up is what a Pi cluster isn't.

Note: This blog post corresponds to my YouTube video of the same name: Why would you build a Raspberry Pi Cluster?. Go watch the video on YouTube if you'd rather watch the video instead of reading this post!

Teaching Ansible with six Raspberry Pis

Originally posted on the Server Check.in blog:

Over the course of this year, I've acquired six Raspberry Pi model 2 B computers, and configured them in a cluster (or 'bramble') so I can use them to test different infrastructure configurations, mostly for running Drupal 8. All the Ansible playbooks and instructions for building the cluster are available on the GitHub project page for the Raspberry Pi Dramble. [...]

The video demonstrates Ansible's simple and powerful model of SSH-based infrastructure management visually. It's been a lot of fun building the Dramble and hacking both the hardware and the software to make this presentation possible!

And the video, Ansible 101 - on a cluster of Raspberry Pi 2s:

The Story of the PING Program

I love finding little gems like this: The Story of the PING Program.

The best ping story I've ever heard was told to me at a USENIX conference, where a network administrator with an intermittent Ethernet had linked the ping program to his vocoder program, in essence writing:

ping goodhost | sed -e 's/.*/ping/' | vocoder

He wired the vocoder's output into his office stereo and turned up the volume as loud as he could stand. The computer sat there shouting "Ping, ping, ping..." once a second, and he wandered through the building wiggling Ethernet connectors until the sound stopped. And that's how he found the intermittent failure.

Don't Wait, Delegate! Proper use of threading and queueing

There are hundreds of ways you can improve your app or website's performance, but few have the potential to improve your app or website's responsiveness as much as queueing or using background processes. There are so many complex operations that can be improved by looking at them in a new way. For example:

Not-so-Instant Oil Change

I like changing the oil in my car, but it often takes a bit of time (definitely not an 'instant!'), and involves the following:

  • Drive to auto parts store, pick up oil and oil wrench, and drive back (30 minutes).
  • Jack up front of car on stands (5 minutes).
  • Drain oil into oil pan, remove old filter, prep new filter (5 minutes).
  • Install new filter, refill oil reservoir (2 minutes).
  • Remove jack stands, clean up mess (5 minutes).
  • Drive to oil disposal center with old oil in pan, and drive back (20 minutes).

Total elapsed time: Over 1 hour! Maybe it's worth spending a few extra bucks on an 'instant' oil change to get back 45 minutes of my life.

How a Hard Drive Works (in Slow Motion)

I've been subscribed to the Slow-Mo Guys' YouTube Channel for a few months now, ever since I noticed some of their great videos of random things that look quite interesting when recorded at over 1000 fps and played back in slow motion.

Their most recent video, How a Hard Drive Works (in Slow Motion) is one of my favorites, not because it's elaborate or amazing, but it's the first time I've ever actually seen the internals of a hard drive in operation. I've ripped apart a few hard drives in my day (they're built like tanks!), and they're amazing on the inside... but to see how quickly those read heads pop back and forth is amazing.

My First Computer (386 PC running MSDOS 6.0)

[Update: I have posted an article about all the computers I've owned].

Pictured below (in the final year of its existence) is the first computer I ever called my own. Built out of scrap parts my Dad brought home from his office, I managed to build the computer as a 33 Mhz 386, with 2 MB of RAM and a 20 MB hard drive, eventually upgrading it (in stages) to a 66 Mhz 486 with 8 MB of RAM and a 512 MB hard drive!

My First PC - 386 DOS Computer
mmm... SCSI in a PC!

How, you may ask, could a diehard Mac/Apple fanboy start on a 386? Well, it was all about budget, you see. Free is good, especially when you're a little kid with absolutely zero dollars in the bank.

Microsoft Windows 7 Launches Thursday. Meh.

"We're living in a different world today," Microsoft Vice President Tami Reller said in an interview with CNET News.

The world is a lot different. That's for sure. It's not the same world that Bill Gates successfully launched Windows 95 into, causing a great stir in the world of personal computing. Anti-Microsoft prejudices aside, I don't know if Microsoft knows this 'new world.'

It's a world where flashy and appealing advertising, and a 'hip' CEO makes your software and hardware seem cool (e.g. Apple). It's a world where free as in beer is the norm, and things don't have to be perfect, but if they work okay and solve problems, people stick around (e.g. Google, Twitter). It's a world where office and work communication and collaboration are no longer tied to a certain computer or operating system—it's all done online (e.g. everyone but Microsoft).

How to Avoid Spyware, Adware, Viruses, etc.

This article will help you to discover ways to avoid malicious software that can cause your Mac or Windows PC problems.

Most Windows users will encounter malicious software at some time or another. But the frequency of these encounters can be greatly reduced by keeping in mind some general tips.

Tips for Avoiding Malicious Software

You should keep in mind a few important things while using your computer to check email, install programs, browse the Internet or chat:

Cleaning Your Desktop or Laptop Computer

This article will help you to properly clean your computer, monitor, keyboard, mouse, trackpad, etc., to keep them looking and working like new.

Keeping your computer clean can not only make it look great, but it can also help your computer to run great. I've seen many really dirty computers (both inside and out) that have problems simply because they are dirty; dust, grime and electricity don't mix well. It is also very hard to see what's on your screen if you have a layer of dirt or grime. And don't get me started on sticky keyboards and mice! Ick!

The following are essential items for cleaning your computer: