Why is a jumper called a jumper

What do the jumper pins on the back of your hard drive do?

There may be pins on the back of your hard drive that nothing is attached to it. These pins are called jumpers and are used to activate certain settings. With modern hard drives, they are only used under certain circumstances.

If you are under a certain age or justI haven't dealt with computer hardware in a long time. Chances are you've never heard of hard drive jumpers. The jumper pins are similar to the pins on the I / O board on a motherboard. You enable certain settings by placing a jumper shunt on certain pins and creating a circuit between them. The settings that activate these jumpers are hard-coded onto the programmed circuit board of a drive.

What do jumpers do? Well, not so much anymore.

Before SATA became the standard interface, computers used the IDE (Integrated Drive Electronics) standard for drives. You may remember the wide, flat, parallel data cables that were used to connect them. A parallel ATA setup required multiple drives to be set up in a computer as master and slave drives. This allowed drives to be identified and prioritized when multiple drives were connected to a single data cable. It is similar to setting "Drive 0" and "Drive 1" on the bus.

PCs don't work that way anymore. The only communication port you'll find on new hard drives is SATA, which offers superior bandwidth in a much smaller package. Why are the jumpers still there? Well, most drives don't have them at all. On those who do this, they enable some special settings.

What exactly the pens do depends on your drive and its manufacturer. For example, on full-size Western Digital SATA hard drives, you can use jumpers to set the following parameters:

  • Pin 1 and 2: Activates Spread Spectrum Clocking (SSC), which helps with excessive electromagnetic interference.
  • Pins 5 and 6: Limits the transmission speed to 3.0 to 1.5 Gbit / s depending on the model.
  • Pins 7 and 8: Enables support for the Extended Format hard drive option in some older versions of Windows.

To find out exactly what the jumpers do, simply search your hard drive for "Jumper Pins" with the model number and manufacturer of your hard drive. You can find the appropriate support website which will tell you which one to use.

Unless you need these special settings, you can ignore the jumper pins on your drive. It will work on pretty much every computer made in the past decade without them. Most of the above options are included for backward compatibility. If you're building a new machine and just want to know what those weird pens are, do it now!

Photo credit: Western Digital