Cloud storage are virtual network disks and are provided by numerous vendors. But what exactly happens with the stored data often cannot be traced. Private data storage media however, offer much more security. It is compatible with most operating systems and devices and, if needed, it can be extended cost-effectively, e.g. with SD cards or hard drives. If the smart phone or tablet is running out of space, the data is easily transmitted via WLAN or Internet to the data storage media. Subsequently, content can be accessed on any device.