Linux inside, Linux inside, every single one of us has Linux inside! (Sung to the tune of “Devil Inside” by INXS—you're welcome for the ear worm, I can't get it out of my head either.)
In the world of embedded systems, systems-on-chip and single-purpose hardware solutions, it's easier to list the products that don't have Linux as their operating system! This month, we focus on putting Linux into tiny places, and that means everything from the tiniest “Android Wear” watch to the ubiquitous Raspberry Pi. As Linux users, we've been sneaking open source into server rooms for decades. Now we get to sneak it in everywhere!
This issue starts with Reuven M. Lerner discussing the books he's embedded into his bookshelf this year. Month after month, Reuven gives us incredible tips, techniques and training for programmers and neophytes like myself. Now we get a glimpse at some of the books he uses for learning himself. Whether you want advice on language books, database books or even some information on freelancing, Reuven shares his stash. If you're looking for your next book to read (after this issue of Linux Journal, of course), check out his column.
Dave Taylor begins a new adventure, this time attempting to parse the written word and grammar with scripts. It's always fascinating to see tasks that are simple for humans attempted by programs and logic. Dave's column is more than just instructive, it will force you to think as well! Speaking of thinking, the title of Kyle Rankin's column this month will make you think hard. “Return of the Mac” seems like the exact opposite of what Kyle would write about. And, of course, he doesn't talk about an Apple product. I won't give it away, but don't worry, Kyle hasn't given up the command line for the GUI world of Apple—in fact, quite the opposite.
I put on my grey hat this month and talk a little bit about SSH. “Hacking” is a word that is used to describe far too many things, most of which I think are more accurately described as, “Using Things Like They Were Made To Be Used”, but that's not as catchy for a movie title. Firewalls are important security tools for any network, but it's important to realize that firewalls can't be your only defense against access. This month I show you why. Do I “hack” the firewall? I don't think so, but for someone unfamiliar with SSH tunneling, it sure looks like it.
Al Audet shows how to embed Linux into a hole in the ground this month. More specifically, he explains how he uses a Raspberry Pi device to monitor the sump hole in his basement to avoid flooding. Sump pumps are amazing devices—until they're not. Al shares not only his method, but also his scripts for controlling a sensor that warns him if the water level rises too much. It's the perfect example of solving difficult problems with Linux. Sachin Verma goes even deeper (pun intended) and shows how to deal with the bootloader on embedded Linux systems. U-Boot is commonly used in such environments, and along with booting the kernel, you can pass environment variables as well. Sachin walks through the boot process and teaches how to customize the information passed on at boot.
Finally, Samuel Bucquet gives a crash course in accessing the BeagleBone Black's I/O ports via Python. Although the Raspberry Pi and BeagleBone Black are both excellent platforms for embedded projects, the BBB's sheer number of I/O options make it incredible for projects with a large number of sensor needs. With Samuel's help, you can access those ports with the friendly and familiar Python language.
The Embedded issue of Linux Journal always makes me want to build something. Now that BirdCam is off-line (the battery in my old Android phone blew up—it was ugly), maybe it's time to start over from scratch. I'm sure there are some great weatherproof IP cameras out there I could use to get better shots of the winter birds. Either way, this is a great issue, and we had a great time putting together for you. Whether you want tech tips, programming ideas or just my silly insight on the best new apps for your phone, the October issue of Linux Journal aims to please!