Plug and play

In computing, a plug and play device or computer bus, is one with a specification that facilitates the discovery of a hardware component in a system without the need for physical device configuration or user intervention in resolving resource conflicts.

Plug and play devices can be due to boot-time assignment of device resources and to hotplug systems such as USB and IEEE 1394 (FireWire).

In the beginnings of data processing technology, the hardware was just a collection of modules, and the functions of those modules had to be linked to accommodate different calculating operations. This linking was usually done by connecting some wires between modules and disconnecting others. For many mechanical data processing machines, such as the IBM punched card accounting machines, their calculating operations were directed by the use of a quick-swap control panel wired to route signals between module sockets.

As general purpose computing devices developed, these connections and disconnections were instead used to specify locations in the system address space where an expansion device should appear, in order for the device to be accessible by the central processing unit. If two or more of the same type of device were installed in one computer, it would be necessary to assign the second device to a separate, non-overlapping region of the system address space so that both could be accessible at the same time.

Some early microcomputing devices such as the Apple II sometimes required the end-user to physically cut some wires and solder others together to make configuration changes. The changes were intended to be largely permanent for the life of the hardware.

As computers became more accessible to the general public, the need developed for more frequent changes to be made by computer users unskilled with using soldering irons. Rather than cutting and soldering connections, configuration was accomplished by jumpers or DIP switches.

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Wikipedia