Jumper
In EIDE drives, a jumper is an electrically-conductive component that you place over pairs of pins that extend from the circuit board on the hard drive jumper block to connect them electronically. For example, a jumper is one way to designate a hard drive as master or slave. The jumper block is located next to the 40-pin connector on the hard drive.
Just-in-time (JIT)
A production and inventory control process in which components and materials are delivered to an assembly point as needed. This process is used in Western Digital manufacturing facilities and in most of the company’s customer plants.