If you are installing a second hard drive into your desktop computer, you need to know how to change the jumper settings on the back of the hard drive. Most hard drives have three jumper settings: Master, Slave and Cable Select. Which setting you choose is determined by the way you wish to configure your drives. Generally speaking, a hard drive set as Master is the primary hard drive from which the computer's operating system runs. Slave drives are normally used as secondary storage or to back up the primary hard drive.
Remove the hard drive from your computer, being sure to disconnect both the power and data cables.
Decide which drive will be the Master and which drive will be the Slave if you are installing more than one drive.
Find the jumper and pins. These are usually located near the right side on the back of the hard drive. You will see a box with 9 pins in two horizontal rows with a vertical jumper covering two of the pins.
Remove the jumper from the pins.
Place the jumper back on the pins in either the Master or Slave configuration. On a Maxtor hard drive, the Master configuration is achieved by placing the jumper on the two vertical pins farthest to the left. The Slave configuration is achieved by removing the jumper completely.
If you purchase an OEM hard drive from a retailer, you may need to buy the jumper separately. Regular retail hard drives typically come with a jumper.