How Is Data Stored On The Disk?
When a file is copied on the disk, it does not necessarily occupy continuous clusters. The operating system starts copying the file from the first available free cluster. If the next cluster is not available then the next free cluster is used. In this way, the file gets fragmented and these chains of fragmented allocation units are stored in the FAT.
What is Data Loss?
Data loss is said to have occurred when:
It does not boot by itself, and does not go to the DOS (C: or D: etc) drive.
- The directories are not listed.
Files are not getting executed or copied.
Files/folders are missing.
This can be due to logical or physical problems on the disk.
When is a disk said to be physically bad?
Not detecting by the system setup.
Detecting but a lot of noise ( clicking or hissing ) is emanating from the disk.
Head is jammed and is not able to read anything from the disk.
Large number of physical bad sectors are present.