The loss of data is an event which means that a database can no longer be used as required (loss
of availability). A frequent form of data loss is that data is deleted accidentally or without
authorisation, for example due to improper use, malfunctions, power failures, soiling or
malware.
However, data may also be lost when devices or storage media are damaged, lost or stolen. This
risk is often particularly high for portable terminal devices and mobile storage media.
Furthermore, it must be noted that many mobile IT systems are not always online. Therefore,
the data stored on these systems is not always up to date. When databases between mobile IT
systems and stationary IT systems are synchronised, data may be lost due to carelessness or
malfunction.
Examples:
• A PDA falls out of someone’s shirt pocket and breaks into pieces on the floor tiles, or a
dog retrieves a mobile phone instead of the newspaper, unfortunately with the
corresponding consequences. These and similar events cause many total losses of data
on portable terminal devices.
• There is malware which selectively deletes data on infected IT systems. For some
malware, the delete function is not run immediately when the system is infected, but
only when a defined event occurs, for example when the system clock has reached a
specific date.
• Many Internet services can be used to store information online. If the user forgets the
password or if the password is not stored, it may not be possible to access the
information stored unless the service provider offers a suitable method to reset the
password.
• Hard disks and other mass storage media only have a limited service life. If no suitable
redundancy measures have been taken, data loss may be caused by technical defects.