Usuario:Juanda/android/filesystem

RAM, Flash, y tarjeta SD

Los dispositivos Android pueden tener tres tipos de almacenamiento: RAM, almecenamiento interno flash, y menos frecuentemente, memoria externa mediante tarjeta SD

La RAM o memoria interna es muy rápida y volatil. Las aplicaciones se cargarán del almacenamiento interno a la memoria RAM. Cuando la aplicación se cierra (¿se cierran?) se liberará dicha memoria.

La memoria interna es el equivalente al disco duro del ordenador. Aquí es donde el sistema operativo del dispositivo (firmware), las aplicaciones, y los datos de usuario se guardan. Las aplicaciones funcionan en modo sandbox, para mantener la seguridad. Hay un usuario linux por cada aplicación instalada.

La tarjeta SD, normalmente se dedica a almacenamiento de usuario, imágenes, vídeos y música. No todos los dispositivos permiten usar tarjetas SD (ejemplo Nexus 4 o iPhone5).

Particiones habituales y directorios

Cada dispositivo puede tener unas particiones distintas. Los que listo a continuación son los más comunes:

• /boot This partition stores the kernel and ramdisk. The kernel can be thought of as the "core" of the device's software. It is what allows the hardware to "talk" to the software, and vice versa. It also controls other aspects of the operating system on the device, such as what file formats the device is able to support. The ramdisk contains the very first bits of Android that are loaded. It's the software that loads everything else.

• /recovery This partition holds the device's recovery software, which gives the user access to special functions, such as upgrading the operating system or making a backup of the device's software.

• /system This is the main directory where the device's essential software, the operating system itself, is stored. When CyanogenMod is installed, this is where it goes. Generally speaking, this partition is loaded into "read only" mode so that you don't accidentally overwrite portions of Android, and it's only able to be modified under special circumstances.

• /cache This directory stores temporary files used by Android. Generally, files on this partition are not usually critical to the operation of the device, and can be "cleared out" by wiping its contents, especially during every major upgrade.

• /data This directory is where much of your personal data is stored. So if you download an app from the Android Market, it goes here. If you change a setting, that change is also stored here. If you receive a SMS, it too is stored here.

• /sdcard This directory contains the stuff from your removable media, such as an SD card. It is used by many apps as a general purpose download space. You can put movies and such on here as well. Even devices without a removable SD card slot may have an /sdcard directory. In this case, it is usually "linked" to a folder in internal storage.