Perkian - Linux
Written by Rich Morin.
Precis: notes on Linux, Perkian, Perkify, and VOISS
Linux plays a vital role in Perkian, Perkify, and VOISS. This note provides some useful background (e.g., “Why Linux?”, “Which Linux?”).
Linux is certainly not the most popular operating system among blind users; that would be Microsoft Windows. Nor is it the most accessible OS; that might arguably be be macOS. So, why are we choosing Linux as the basis for Perkian and Perkify?
We’re glad you asked (:-). The primary reason has to do with legal restrictions and cost. Because Linux is both libre and gratis, we can obtain, modify, and redistribute it without paying fees to anyone. This frees us to make any desired changes and give the result away.
A related reason has to do with the relationship between Linux and the rest of the open source software community. Although free and open source software can be ported to other systems, it is generally developed on and for Linux. So, more packages are readily available and things (typically) Just Work.
The lineage of Linux also plays a part. Because it was strongly inspired by Unix, Linux shares that system’s orientation towards text-based tooling. Administrative functions can all be performed on the command line and/or by editing text files. The base Linux distribution has a wealth of text-based commands and add-on packages provide even more. Although text-based packages are not always accessible to the blind, they have a far better chance of being so than GUI-based apps.
Finally, although there are a variety of window managers for Linux systems, they are all based on the X Window System (aka X11). Unlike the native window managers in macOS and Microsoft Windows, X11 is designed to be used in a distributed fashion, with clients and servers running on isolated machines. This is particularly relevant to Perkify. A (sighted) user can run GUI-based applications on the Perkify virtual machine and access them on the host platform.
Almost six hundred Linux distributions exist, with close to five hundred out of those in active development.
Although these distributions are all based on a common kernel, they vary markedly in terms of popularity, what other software they include, how (and how often) updates are released, which instruction set architectures they support, etc.
Although this might seem overwhelming on first inspection, these variations provide useful criteria for projects trying to decide on a base distribution. For example:
Popular distributions have more support, in terms of add-on packages, documentation, etc.
Some distributions target cautious, naive users; others target experienced, adventurous ones.
The distribution needs to support the target hardware (e.g., architecture, devices, interfaces).
The expected users may prefer infrequent, stable releases over (say) rolling releases.
F123Light (used by VOISS) is based on Arch Linux ARM, a variant of Arch Linux for the ARM architecture (as used in Raspberry Pi systems). Although Arch Linux tends to target experienced users, F123Light adds a “talking”, menu-based interface which caters to the needs of blind, naive users.
Perkify is based on the X86-64 variant of Ubuntu, a very popular distribution which targets casual users. Ubuntu, in turn, is based on Debian, whose Advanced Package Tool (APT) is well respected (and supported by over 25,000 packages). Ubuntu releases occur every six months and are based (with additional integration and testing) on Debian’s so-called “unstable” branch.