Android secrets

Reviewing mapmywalk on a rooted phone reveals 9MB of files. It's amazingly complex for such a simple, clunky app. 7MB is used by the webview page renderer to render its user interface out of HTML. Another 28k is used by crash reporting software provided by crashlytics, another corporation just focused on that. A small amount is the map tiles. Then we have 1.5MB which seems to be the persistent state of the program. It's split between sqlite files & xml files.

The time & distance values are stored in the same XML file as the preferences. A value like totalDistanceMeters must entail massive numbers of flash writes. It must have been faster than recalculating from the stored route. A timer is stored as startTimeMsec & pauseTime. The databases don't store any frequently updated data.

The route temporaries are text files. There's no emphasis on compactness, only abstraction. Literally everything required to restore the current state is in flash. It's a real case of the operating system dictating the application.


It uses libnmsp_speex for speech synthesis, even though Android can do it by default. It uses libKalmanFilterJni probably for estimating speed & distance. It's a huge amount of complexity for what it does, but normal for any modern program. That's why something as conceptually simple as a thermostat can fetch a $2 billion buyout. There are huge algorithms going into the simplest modern programs.