Top: jumper block on IDE hard drive with shunt; bottom: assorted shunts

In electronics and particularly computing, a jumper is two or more connecting points that can be conveniently shorted together to set up or adjust a printed circuit board, such as a computer's motherboard. Image File history File links Download high resolution version (854x814, 238 KB) Summary Taken March 30, 2006. ... Image File history File links Download high resolution version (854x814, 238 KB) Summary Taken March 30, 2006. ... ATA cables: 40 wire ribbon cable top, 80 wire ribbon cable bottom Advanced Technology Attachment (ATA), is a standard interface for connecting storage devices such as hard disks and CD-ROM drives inside personal computers. ... Typical hard drives of the mid-1990s. ... The field of electronics is the study and use of systems that operate by controlling the flow of electrons (or other charge carriers) in devices such as thermionic valves and semiconductors. ... Originally, the word computing was synonymous with counting and calculating, and a science that deals with the original sense of computing mathematical calculations. ... For alternate meanings see Short circuit (disambiguation) A short circuit (sometimes known as simply a short) is a fault whereby electricity moves through a circuit in an unintended path, usually due to a connection forming where none was expected. ... Close-up photo of one side of a motherboard PCB, showing conductive traces, vias and solder points for through-hole components on the opposite side. ... An illustration of a modern personal computer. ... An old Octek Jaguar V main board with an AMD 386DX-40 processor. ...

Jumpers are arranged in groups called jumper blocks, each group having at least one pair of contact points and often more. In general, each contact in a jumper block terminates in a small metal pin. An appropriately sized conductive sleeve called a shunt is slipped over the pins to complete the circuit. (In everyday usage, shunts are very commonly but incorrectly called "jumpers".) Hot metal work from a blacksmith Look up Metal in Wiktionary, the free dictionary. ...

Jumper shunts are almost always metal, and are usually encased in a non-conductive block of plastic for convenience, and to avoid the risk that an unshielded shunt will accidentally short out something critical (particularly if it is dropped onto a live circuit). Plastic covers a range of synthetic or semisynthetic polymerization products. ...

When a jumper shunt goes over two (or more) jumper pins, current is carried across, and the electronic equipment is thus instructed to activate certain settings accordingly. For example, computer CPU speed and voltage settings are often made by setting jumpers. Informally, technicians often call setting jumpers "strapping". To adjust the SCSI ID jumpers on a hard drive, for example, is to "strap it up". CPU redirects here. ... International danger high voltage symbol. ... Typical hard drives of the mid-1990s. ...

As a general rule, the early generations of any given technology have many jumpers, often laid out in a way that is badly documented and difficult to set correctly. As time goes by, the designers find ways to streamline and simplify the jumper layout. For example, a typical early model Intel 386 motherboard might have 30 or 40 jumper pairs, while the last production models typically had just a handful, or sometimes only one. Typically, each jumper is assigned and labelled with a number, which is referred to in an instruction list printed on the motherboard or in the manual. The Intel 80386 is a microprocessor which was used as the central processing unit (CPU) of many personal computers from 1986 until 1994 and later. ...

The recent trend has been to try to eliminate jumpers entirely from hardware devices by the use of auto-configuration or software-controlled configuration. Configurations may be stored in NVRAM, loaded by a host processor, or negotiated at system initialization time. In some cases, hot pluggable devices may be able to renegotiate their configuration. Jumperless designs have the advantage that they are usually fast and easy to set up, often require little technical knowledge, and can be adjusted without having physical access to the circuit. Auto-configuration is the automatic configuration of devices without manual intervention, without any need for software configuration programs or jumpers. ... Non-Volatile Random Access Memory (NVRAM) is a computer memory chip which will not lose its information when the power is lost. ... Plug and Play is a term used in the computer field to describe a computers ability to have new devices, normally peripherals, added to it without having to restart the computer. ...

More traditional systems using boards with physical jumpers, on the other hand, tend not to be mis-set by end users (as, in general, non-technical people are less willing to physically alter hardware settings than they are to experiment with settings from the keyboard). They also have the advantage that they usually only ever need to be set once: while firmware settings can be easily lost or corrupted by a careless user, a virus or a power failure, the only way to alter a correct jumper setting is to physically change it. In computing, firmware is software that is embedded in a hardware device. ... In computer security technology, a computer virus is a self-replicating or self-reproducing-automation computer program that spreads by inserting copies of itself into other executable code or documents. ...