How to Destroy a Hard Drive Without Anyone Knowing

Having a hard disk is great for storing some personal files. But storing large amounts of data directly on the disk for extended periods of time is bad for your files and your hard drive. Doing so significantly increases the number of viruses running around, and increases the chances of data loss. In order to give your data the best possible chance of surviving a hard drive failure, be sure to format the drive with an adequate level of data protection. You can find out more about this from the article How to format a hard drive.
Warning: Never accidentally overwrite a data area.

Hard Drive Recycling

If you’ve decided to destroy your hard drive, or refresh it, remember to format it with an adequate level of data protection:
To format your drive, first check the documentation that came with your drive. Then follow the steps below to format your drive. If the operating system is macOS, you’ll need to restart your computer to execute the command that removes data from your hard drive. In operating system form, you can find this option in the function key (F3) after pressing the power button.
If you’re using another operating system, stop your computer, and then press the data question mark button at the main macOS screen. Then, enter the following command.
Viola! The format process has begun. The next step is for you to insert your new drive into your computer in order to continue from where you left off.
It’s likely that your Flash update utility informs you that your old hard drive has failed.

format method, you might want to consult the official Apple documentation (which is quite lengthy). Then you’ll format the drive according to the instructions
given in your documentation. Start by unplugging the drive from your computer. Hold down the
sectors i and j (or power and reset) simultaneously, while unplugging the tape
connector.
The next step involves formatting the drive to make it fit for future use. Format the drive to
ATA Disk. Choose Format as Partition in the following menu (note that you can
choose Format as.img from here as well).
A) Select the Primary partition.
B) Choose the Check empty spot option. Choose Create partition, then next. Your newly formatted GPT type partition should appear immediately.
Back up your files as you might need them in the future. Mount it using
mount /dev/disk2 /mnt/articles
Now you’ve got yourself a 64GB drive. To use it, do a few steps.
Though it’s relatively slow, all NTFS partitions work fine on this drive. You can
unmount the parent by
umount /dev/disk2
You’ll be asked to enter the administrator password (by default it’s already
present). Enter it when asked.
Now we’ll refill the hard drive.

Native tool and not your hardware one. select the remainder of the disk for bootable from external media.

Hard Drive Recycling
Hard Drive Recycling

After formatting everything to bootable media you’ll modify the partition table and
append swap and active memory to it. After that, the next time your Mac asks
to continue you’ll receive a prompt to install updates. This will leave the
system in an incomplete state and you’ll have to format it to complete your job.
Now that we understand the procedure to create an ATA formatted external drive it’s
a good moment to write-up the steps we’ve already covered. You don’t need any special hardware,
an ethernet cable, etc and the external drive is already plugged into your
computer.

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