Purism following its strict philosophy uses and installs completely free software, meaning there is no mystery software running anywhere within the kernel, the operating system, nor any software applications. To elaborate on what the means, and why the Librem 15 is the first laptop shipping with completely free software, let’s deconstruct a computer into its main parts where software is required.
When power is provided, all hardware components spin up, and load the firmware they have burned onto them, such as the hard drive or solid state drive, the BIOS then loads firmware for additional components, be that the memory controller, system management controller, embedded controller, USB, and/or GPU. At this point the BIOS hands off to a boot loader, Purism uses GRUB, which is a completely free boot loader. A boot loader is the first software program that runs when a computer starts. It is responsible for loading and transferring control to the operating system kernel software, Purism uses a completely free version of Linux. The kernel, in turn, initializes the rest of the operating system, Purism uses a completely free version of GNU. GNU allows for thousands of free software applications to run on top of it, and the distribution that Purism uses to bundle completely free software applications is Trisquel.