Reliably committing data to the media through the Linux kernel

Embedded devices used to be simple – the path taken by the data from the point of capture to the media was very direct. Today’s devices use a less direct path for the data, mostly due to the larger size of modern data capturing on the media. With more coders than ever building applications for a Linux or Android environment, a knowledge of how to reliably commit the data to the media is of vital importance.

This paper explains details of the Linux write-behind cache, flush, and fsync calls. We focus on how file systems behave in these situations, touching on two reliability techniques – journaling and transaction points.