How to Format a Hard Drive

This article includes the basics for formatting a hard drive.
Steps
For Windows 9x
1. If you want to save any of the data on the disk, back it up by copying it to a CD or another hard drive. Formatting will destroy ALL of the data on the disk.
2. Use a startup floppy (sometimes called a "boot disk") to obtain a DOS prompt.
3. Type FORMAT C:
4. Give the process some time to complete. Install your operating system of choice, or use the blank disk for another purpose.
For Windows XP
1. If you want to save any of the data on the disk, back it up by copying it to a CD or another hard drive. Formatting will destroy ALL of the data on the disk.
2. Use the Windows XP CD-ROM to boot the computer.
3. Select the "Recovery Console" option.
4. At the prompt, type FORMAT C:
5. Give the process some time to complete. Install your operating system of choice, or use the blank disk for another purpose.
For Unix-based operating systems
1. Boot from a livecd or diskette
2. Open a terminal window (usually something like xterm or konsole)
3. Log in as root by typing su and entering the password
4. Type mkfs.ext2 /dev/hdaxx where you change the ext2 by the filetype you want (e.g. ext2, ext3, reiserfs,...) and the axx by the letter of your drive and the number of the partition you want to format. (e.g. /dev/hda1, /dev/hdc32,...) You can also use mke2fs -j if you want an ext3 file system.
Tips
1. For more secure formatting, there are programs available which write zeros or garbage characters over the entire disk, making the deleted information unrecoverable.
2. C: and /dev/hda are your primary hard drive. If you are trying to format a secondary drive, replace C: and hda with the appropriate drive letter--D: or /dev/hdb, for example.
Warnings
1. Make sure that you format the correct drive, and that you have backed up any data you don't want to lose.