Go to TogaWare.com Home Page. GNU/Linux Desktop Survival Guide
by Graham Williams
Duck Duck Go

Wipe Disk

When data is deleted from a hard disk the actual 1's and 0's are not removed from the disk, as such. Instead the directory information about the name and location of the file is lost and the area where the file was stored is made available for overwriting by other data. This means that the original data can be recovered even though the file has been deleted (but possibly not yet overwritten).

This is great if you have accidentally deleted data and need to recover it. There exist forensic tools to do this. A technique called Magnetic Force Microscopy (MFM) allows, at a cost, the recovery of even the last two or three layers of data as written to disk! But today's hard disks are also clever in dealing with bad blocks and may unwittingly store some of your data permanently in places that no one generally has access to!

However, if you are wiping a disk for return to someone else, or never plan to use the disk again, you may want to ensure that you have completely removed any trace of your possibly confidential data from the disk. The wipe package in Debian GNU/Linux provides a tool to do this.

  $ wipe -kD /dev/sdb1
  $ wipe -kD /dev/sdb2


Support further development by purchasing the PDF version of the book.
Other online resources include the Data Science Desktop Survival Guide.
Books available on Amazon include Data Mining with Rattle and Essentials of Data Science.
Popular open source software includes rattle and wajig.
Hosted by Togaware, a pioneer of free and open source software since 1984.
Copyright © 1995-2020 Togaware Pty Ltd. . Creative Commons ShareAlike V4.