Why is postmarketOS based on Alpine Linux?
The biggest upside is, that Alpine is small. The base installation is about 5 MB! Only because of that, our development/installation tool pmbootstrap is able to abstract everything in chroots and therefore keep the development environment the same, no matter which Linux distribution your host runs on.
And if you messed up (or we have a bug), you can simply run pmbootstrap zap and the chroot will be set up again in seconds. Imagine how long it would take to do the same with Debian (which is a fine distributions for plenty of other use cases).
Another angle on the tininess of Alpine - many older devices don't have much space to spare, so hilariously tiny system images can be quite useful or even required.
Will Android apps be supported?
Currently, our best bet seems to be getting Waydroid running on postmarketOS. It's highly recommended to use native Linux applications though, as there are some downsides to Android apps:
- Freedom issues (most are proprietary, or only work together with a proprietary network, some even track you), see F-Droid for FLOSS programs, that respect your freedom.
- Heavy resource usage: With all resources, we will most likely need to run a Android environment next to your regular Linux. So it will use up more RAM and CPU compared to native Linux applications.
So at least try to find a native-Linux alternative for your favorite application or ask yourself if you really need it. For app developers, consider using Kirigami UI, MauiKit, or similar to develop apps for both mainstream mobile OSes (Android/iOS) as well as natively for Linux distributions. Kirigami and MauiKit apps can also be convergent and work well on desktop OSes, too. You can also use libadwaita to create great Linux phone and desktop apps, but Android and iOS are unsupported.
Can project Treble help postmarketOS?
Google proposed Treble to improve the update situation for Android by having a "vendor implementation" with a stable API, that Android builds upon. The idea is, that you can swap out the Android version easily, because of that API. As postmarketOS developers see it, that is a step in the right direction, but it does not resolve the updates problem completely.
You will still have the "vendor implementation", which is different for every device. It will contain at least the kernel and drivers (kernel/userspace), for which you, as a user, depend on the manufacturer to keep it updated, and which will probably not be mainlined. This means, that after two years or so, when the support runs out, you will still have a device, that does not get updates anymore. Only for a smaller component of the operating system.
Also keep in mind, that this will work for newer Android O phones only. We already have an alarmingly high number of phones, which will never get that improvement. They can be saved from being electronic waste with projects like postmarketOS.