Data loss: Where is my deleted files?

Have you experienced data loss whether you accidentally deleted your files or do not have any clue why the data you have saved lost?  There are two major reasons for data loss. Data loss can be caused by software (e.g. virus, mis-format, mis-clone, deletion) as well as hardware (bad sector, power cut, head damage, circuit panel problem) reasons. So when you delete your data, most of the time you don't delete them completely. The data are still in the memory just that the computer point elsewhere. Its just like marking the contents of a book as empty although the actual chapter is still there. In a hardware case, one example of a data loss can be caused by misalignment between the read/write head and the tracks on the spinning plate. Software related data loss can be recovered using data recovery software whereas hardware related data loss needs hardware fixing or replacing parts.In a new secondary storage like Solid State Drive (SSD) and Solid State Hybrid Drive (SSHD), the recovery is much harder since the new storage use NAND flash technology which utilize integrated circuit assemblies as memory. Unlike its Hard Disk Drive (HDD) predecessor, the data inside flash based memory is not easy to tap and recovered.