What Linux Kernel Does Accelerated Use?

Digi International Digi International
March 28, 2017
At Accelerated Concepts, the Linux kernel is at the heart of our hardware development. It provides a powerful and secure software engine upon which we build our world-leading cellular networking solutions.
So, what Linux kernel do we use?
Our engineering team has dozens of years of experience developing with and embedding the Linux kernel into critical networking equipment. We dont just take an off-the-shelf kernel or Linux system from other vendors and shoehorn it into our hardware designs. Instead we build our software from the ground up to be perfectly tailored to our hardware; the goal is to provide an exact fit for our customers.
At Accelerated we start with a "mainline" (sometimes called “vanilla”) Linux kernel. Those are the source packages directly released by Linux creator Linus Torvalds. Mainline source packages are first released online at www.kernel.org.
We strive to keep our kernels as current as possible. So from time to time, at regular intervals, we upgrade the Linux kernel used in our products. The current model for kernel development anticipates new versions every 2 to 3 months. Occasionally – typically once a year – the Linux community designates a kernel as a "long-term" supported release. Accelerated bases its products on these long-term release kernels.
Moving to newer kernel versions is a critical step in keeping our product updated. Newer releases inevitably fix bugs – sometimes bugs with serious security implications. These newer kernels can also provide additional features, like network protocols, performance optimizations, and support for newer hardware (CELL modems for example), just to name a few. There are many advantages to keeping kernels up to date.
Currently (as of this posting) all Accelerated products are based on a 4.4 Linux kernel. Previously we have used kernel versions 4.1, 3.18, and 3.10. We are currently working to introduce product firmware using the 4.9 Linux kernel in early 2017.
All Accelerated hardware is built around the same base source code, meaning all our products run firmware using the same Linux kernel. We do not keep separate source code bases for different products. When we prepare to switch to a new kernel, we spend a lot of time extensively testing it across all our device platforms.
Our engineers extend the kernel as required with additional hardware support, things like unusual device drivers, platform device trees, or just plain old bug fixes that optimize the kernel. Our engineers often share these customizations with the Linux community, at times being recognized as major contributors toward the sustained development and support of a kernel release (https://lwn.net/Articles/620827/).
At Accelerated Concepts we are not just users of the Linux kernel, rather Linux is an integral piece of technology that we strive to advance as members of the development community.
It truly is at the heart of what we do.