How to Write Zeros to a Hard Drive
Writing zeros to a hard drive is quite easy. All you need is a special Linux distribution, called Knoppix, that runs completely off of CD or DVD so you don't need to install anything on the hard drive. This means even non Linux users can write zeros on a hard drive. In just a few steps, you can write zeros to a hard drive to erase it beyond any possibility of recovery.
- Difficulty:
- Easy
Instructions
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1
Download Knoppix Linux from the Knoppix website. There is a link to Knoppix in the Resources section below.
Knoppix is completely free.
The CD version is kept more up to date and is much smaller than the DVD version. This means it will take much less time to download (less than an hour for the CD versus around 8 hours for the DVD).
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2
Burn the Knoppix ISO to CD or DVD.
Use a ISO burning program such as Nero to burn the Knoppix ISO file to CD or DVD.
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3
Boot up Knoppix from CD or DVD.
Nothing will be installed to the hard drive.
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4
Identify the hard drive you are going to write zeros to.
Once you are at the command prompt, determine which hard drive is going to be erased. Here is a list of devices:
/dev/hda = primary master IDE
/dev/hdb = primary slave IDE
/dev/hdc = secondary master IDE
/dev/hdd = secondary slave IDE
/dev/sda = first SCSI hard drive
/dev/sdb = second SCSI hard driveIf you are having trouble figuring out which hard drive it is, try running the command fdisk. If you still have trouble figuring this stuff out, you may be better off using a commercial product to write zeros to your hard drive.
WARNING: If you mess this step up and misidentify the hard drive, you may accidentally write zeros to a hard drive that you actually wanted to keep.
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5
Write zeros to the hard drive with the following command (using /dev/hdb as an example):
dd if=/dev/zero of=/dev/hdb bs=1M
WARNING: This will destroy all data, the boot sector, and all partitions. The entire disk will be full of zeros. If you really want to be sure everything is gone, run this command a few more times.
After this process is complete, you may dispose of the hard drive or use it again, minus the data that was there before.
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- Photo Credit Molla Zi
Comments
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Nope, the sectors that were overwritten are gone forever and it seems as though the sectors it wrote over were pretty vital.
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Hello, I have a BIG problem... I misidentify sdb (blank HD) like sda (I had 2 partition, one with Ubuntu and other with data), and then run this command over my sda!!!. Just a few seconds (no more than 2 seconds). But now I cannot access to sda... anyway to repair or recover my data?? :(
