On 30 September 2005 22:50, Remy Blank wrote: > Mark Knecht wrote: > > Sold my laptop on Ebay. It was dual boot Gentoo/XP Pro and had > > financial data on it. I'd like to pretty securely wipe the drive > > before shipping. I've already deleted all 10 partitions and written > > new partitions on which are different sizes and different file > > systems. What simple command can Ido to write data to the whole drive? > > Assuming your hard disk is /dev/hda, I'd do: > > dd if=/dev/zero of=/dev/hda bs=8M > > Then go have a coffee. If you want it more secure, go for this, a few > times in a row (at least 7, I read): > > dd if=/dev/urandom of=/dev/hda bs=8M > > However, this will take a *long* time, as /dev/urandom is quite slow. > But it will make the data unrecoverable even with expensive means.
This doesn't really wipe out all data securely. It can still be recovered by special hardware. If you do both dds alternately 7 times, your data is gone. Reason: Writing zeros seven times to the harddrive doesn't change the magnetic properties much. Ideally, you should write zeros and 255s alternately several times. Uwe -- 95% of all programmers rate themselves among the top 5% of all software developers. - Linus Torvalds http://www.uwix.iway.na (last updated: 20.06.2004) -- [email protected] mailing list
