Open main menu
Home
Random
Recent changes
Special pages
Community portal
Preferences
About Wikipedia
Disclaimers
Incubator escapee wiki
Search
User menu
Talk
Dark mode
Contributions
Create account
Log in
Editing
Disk formatting
(section)
Warning:
You are not logged in. Your IP address will be publicly visible if you make any edits. If you
log in
or
create an account
, your edits will be attributed to your username, along with other benefits.
Anti-spam check. Do
not
fill this in!
==== Disk-filling ==== When the hard drive's built-in reinitialization function (see above) is unavailable due to driver or system limitations, it is possible to fill the entire disk instead. On older hard drives without [[bad sector]] management,<ref>{{cite web |title=BadBlockHowto β smartmontools |url=https://www.smartmontools.org/wiki/BadBlockHowto |website=www.smartmontools.org}}</ref> a program will also need to check for any damaged sectors and try to spare them out. On newer drives with defect management, reallocated sectors may be left unerased, whereas the built-in re-initialization function will erase them.<ref name="Secure Deletion" /> In modern times, it is most common to fill hard drives with value of <code>0x00</code>. One popular method for performing this zero-fill operation on a hard disk is by writing zero-value bytes to the drive using the Unix [[dd (Unix)|dd]] utility with the [[/dev/zero]] stream as the input file and the drive itself (or a specific partition) as the output file.<ref>{{cite web|url=http://www.myfixlog.com/fix.php?fid=58|title=How to Securely Erase (Wipe) a Hard Drive for Free with DD|website=myfixlog.com|archive-url=https://web.archive.org/web/20160418143615/http://www.myfixlog.com/fix.php?fid=58|archive-date=April 18, 2016}}</ref> This command may take many hours to complete, and will erase all files and file systems. A value of <code>0xFF</code> is used on flash disks to reduce [[Program-erase cycle|wear]] . The latter value is typically also the default value used on ROM disks (which cannot be reformatted). Some advanced tools allow configuring the fill value.<ref group="lower-alpha" name="NB_Format_Wipe"/> Zero-filling a drive is not a secure method of preparing a drive for use with an encrypted filesystem. Doing so voids the [[deniable encryption|plausible deniability of the process]], as the encrypted areas (indistinguishable from random without a key, unless the cipher is compromised) will stand out among zero blocks. The correct technique is to zero-fill inside a temporary encrypted layer then discard the key and layer setup. ([[/dev/urandom]] provides similar safety, but tends to be slow.)<ref>[http://www.globallinuxsecurity.pro/quickly-fill-a-disk-with-random-bits-without-dev-urandom/ Quickly fill a disk with random bits]</ref>
Edit summary
(Briefly describe your changes)
By publishing changes, you agree to the
Terms of Use
, and you irrevocably agree to release your contribution under the
CC BY-SA 4.0 License
and the
GFDL
. You agree that a hyperlink or URL is sufficient attribution under the Creative Commons license.
Cancel
Editing help
(opens in new window)