Different BlackBerry® devices support different types of memory. The following types of memory are possible on BlackBerry devices:
- Application storage is internal to the BlackBerry device. It contains the operating system, Java® Virtual Memory (JVM), and an internal file system. Application storage is also called flash memory and onboard memory. Application storage is the only place on a BlackBerry device from which applications can be run. All BlackBerry devices have application storage.
- External media card storage is a microSD card that BlackBerry device users can insert to extend the storage on their device. It is optional and removable. A File Allocation Table (FAT) file system is mounted on the media card. MicroSD cards are supported on all devices running BlackBerry® Device Software 4.2 or later, with the exception of the BlackBerry® 8700 Series.
- Built-in media storage is an embedded multimedia card (eMMC). It is not removable. A FAT file system is mounted on the built-in media card. Built-in media storage is also called internal media memory and on-board device memory. Built-in media storage is included on many newer devices.
When you consider where to store essential data, keep in mind that microSD cards can be removed. Data can be corrupted if the card is removed while data is being written. For both external media card storage and built-in media storage, data can be corrupted if the battery is removed from the device while data is being written. Application storage is more robust in these situations.
There is more latency in writing to application storage than there is in reading from it. For example, reading from the persistent store is relatively fast while commits are relatively slow.