White paper | Xperia™ E4
18
February 2015
On the other hand, when it comes to reading from an external SD Card, you will be able to access content
(for example, videos, photos and music) on a memory card inserted in this slot without any special
consideration since the Android system searches all available memory for content. Therefore, such
products may be regarded as supporting a fourth type of memory, called “External Card” or “SD Card”.
4.
SD Card
(known as “/ext_card” from a programmer’s point of view, or by other names in other Android
products) is the name for the removable SD memory card in all 2015 Sony Mobile products. As
described in the previous section, this External Card memory is generally more limited in that any
application can read from it, but many applications cannot save to this card. Only a few applications,
including backup applications and file manger applications, have the capability to save to this card.
Backing up data to different memory types
Generally, you should not save photos, videos and other personal content solely on the internal memory
of a device. If something should happen with the hardware, or if the device is lost or stolen, the data
stored on the device’s internal memory is gone forever.
In a device where an SD card reader is the main memory, it is relatively easy to take the card out and copy
all content to a PC or Mac, or to an entertainment device with a memory card slot. In a product featuring
Internal Storage as the main memory, it is not possible to physically remove the memory. Instead, any
critical or high-value content must either be copied to an external SD card by a special backup
application, transferred to remote storage over a network (mobile or Wi-Fi), or to a computer via a USB
cable.
To facilitate the transfer of data via a cable, the Xperia™ E4 supports Media Transfer Protocol (MTP),
which makes it possible to easily transfer content back and forth between your device and a Windows®
PC. For Apple™ Mac® computers, a special application called Sony™ Bridge for Mac is available with
built-in support for MTP. This application can be downloaded from the Xperia™ E4 support page.
Note that you do not need to back up or make a copy of applications that you have downloaded from the
Google Play™ Store. They can normally be downloaded again after you have set up your Google account
to work in a new device (or in a device where the memory has been completely erased).
Note 1
:
Some Android devices, including Sony Mobile devices from 2012 and Sony Ericsson devices from 2011
and earlier, do not use a single “Internal Storage” for both applications (and their data) and user content.
Instead, these devices use either an external SD card for user content, or a corresponding area of internal
memory to reproduce the functionality of an SD card. In such devices, there is a fixed limit between the
application area (“/data”) and the user content area (“/sdcard”), with the result that user content can build
up and reach this limit. When the user content reaches this limit, no additional data can be added using
any application. For example, the camera application would no longer be able to capture additional
photos even if a considerable amount of free space was available in the application area. This limit also
applies to the application area. Downloading and installing new applications would not be possible even if
there was enough free memory in the user content area.
Note 2
:
Some devices with integrated storage have abandoned the distinction between the application area and
the content area when it comes to a Factory Data Reset. As a result, there is no option in such devices to
perform a Factory Data Reset and preserve content. In such devices, all content is completely deleted
from the device when a reset is performed.
In contrast, Sony Mobile’s memory integration solution makes it possible to preserve user content in this
situation. Therefore, when performing a Factory Data Reset, the default action will still be to only remove
applications and their data, and an option box must be checked if all content is to be removed as well (as
might be desirable when selling the device second-hand).
