Or another example with the Arch Linux image written to a 4GB USB thumb drive: I/O size (minimum/optimal): 512 bytes / 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes This is an example for a HDD formatted to boot a linux system: Use fdisk to locate all read/write devices the user has read access to.Ĭheck the output for lines that start with devices such as /dev/sd"X". Indications otherwise refer to single residual bits reconstruction of byte patterns is generally not feasible. Note that repeating the operation should not be necessary nowadays.
#GDISK WIPE DOD FULL#
However because of block sizes, these sections would only amount to a few theoretically recoverable KiB.Ī single, full overwrite with zeros or random data does not lead to any recoverable data on a modern high-density storage device. Thus a full overwrite would not reach it. If a hard drive marks a sector as bad, it cordons it off, and the section becomes impossible to write to via software.
#GDISK WIPE DOD GENERATOR#
To prepare a drive for block device encryption inside the wiped area afterwards, it is recommended to use #Random data generated by a cryptographically strong random number generator (referred to as RNG in this article from now on). Most notably, all Flash memory based devices and older magnetic storage (old HDDs, floppy disks, tape). There are different wiping issues with different physical storage technologies. In case of a HDD, data recreation will not be possible without at least undocumented drive commands or tinkering with the device's controller or firmware to make them read out for example reallocated sectors (bad blocks that S.M.A.R.T.
#GDISK WIPE DOD SOFTWARE#
Any file recovery software mentioned above then would need to be specialized on proprietary storage-hardware features. If you want to quickly wipe everything from the disk, /dev/zero or simple patterns allow maximum performance while adequate randomness can be advantageous in some cases that should be covered up in #Data remanence.Įvery overwritten bit means to provide a level of data erasure not allowing recovery with normal system functions (like standard ATA/SCSI commands) and hardware interfaces. There may be (unencrypted) data left on the device and you want to protect against simple forensic investigation that is mere child's play with for example File recovery software. The most common usecase for completely and irrevocably wiping a device is when the device is going to be given away or sold.