<P> When a partition is deleted, its entry is removed from a table and the data is no longer accessible . The data remains on the disk until being overwritten . Specialized recovery utilities, (such as TestDisk, AOMEI Partition Assistant, M3 Partition Recovery and gpart), may be able to locate lost file systems and recreate a partition table which includes entries for these recovered file systems . Some disk utilities may overwrite a number of beginning sectors of a partition they delete . For example, if Windows Disk Management (Windows 2000 / XP, etc .) is used to delete a partition, it will overwrite the first sector (relative sector 0) of the partition before removing it . It still may be possible to restore a FAT or NTFS partition if a backup boot sector is available . </P> <P> HDDs can be compressed to create additional space . In DOS and early Microsoft Windows, programs such as Stacker (DR - DOS except 6.0), SuperStor (DR DOS 6.0), DoubleSpace, or DriveSpace (Windows 95) were used . This compression was done by creating a very large file on the partition, then storing the disk's data in this file . At startup, device drivers opened this file and assigned it a separate letter . Frequently, to avoid confusion, the original partition and the compressed drive had their letters swapped, so that the compressed disk is C:, and the uncompressed area (often containing system files) is given a higher name . </P> <P> Versions of Windows using the NT kernel, including the most recent versions, XP and Vista, contain intrinsic disk compression capability . The use of separate disk compression utilities has declined sharply . </P>

What is primary partition and extended partition in linux