Optical media (CD, DVD, BluRay)As with other media, it is also possible that optical media suffer from data loss.
Hardware damageThe most common hardware damage that occurs with optical media are scratches to the surface, which do not necessarily have to be visible to the naked eye. A scratch that appears at an unfavourable location, for instance continuously from the outer edge up until the centre of the disk, will inevitably lead to data loss. Likewise, optical media is extremely sensitive to sunlight and temperature fluctuations. Even the smallest chemical changes within the coating of the data medium can already cause the loss of data. However, in most of these cases a data recovery remains possible. Time and again we also receive optical media that has been broken. In these cases, a reconstruction is only possible with a great deal of work. Several man-months of labour must be invested.
Session has not been ended correctlyThe most common cause of data loss in an optical medium however is caused by an incorrectly ended session, i.e. the recording process was not completed correctly. The medium subsequently appears as if it is completely filled, however no data is displayed. Likewise it can occur that only a fraction of the actual capacity is indicated as the maximum available. In these cases, the data is still present, however the method with which the data can be accessed again is very complex and can only be performed with the use of special hardware. For this, the technician tasked with the data rescue will use especially manipulated CD, DVD or Blu-ray drives.
Source of the error: The authoring softwareIn many cases, following the recording process, a verification whether all data has been successfully transferred to the medium is not performed. Time and again the authoring software fails to write certain data. Possible causes are for instance the data size and non-standardized file names. When this is only discovered later on, users often erroneously think that data has simply been “lost” in the course of time.
Re-writable optical mediaIn the case of re-writable media, data that is present can be deleted. However, when this deleted data should be recovered again, in principle, this is performed in the same manner as with a hard disk, however it is more difficult because following a deletion, drives do not permit access and especially manipulated drives must be used.
Additionally, it must be taken into account that re-writable optical media can always only be written from the beginning until the end and the data is only physically present for as long as it has not been overwritten again.
- Forensic analysis of a damaged CD
Your next steps
Assistance in the case of data lossIn most cases, data loss leads to a state of emergency. Please contact us! Our job is to reduce the damage you experience resulting from data loss to a minimum.
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