Hot plugging (also called hot swapping) is the ability to add and remove devices to a computer system while the computer is running and have the operating system automatically recognize the change.
This is useful when a system component fails as it enables a new device to be installed without system downtime. Two external bus standards — Universal Serial Bus (USB ) and IEEE 1394 — support hot plugging. This is also a feature of PCMCIA.
Hot Plug Versus Hot Swap
While the terms hot plugging and swapping are used interchangeably, hot-pluggable devices typically require administrative tasks to complete the switch (i.e. mounting the hard drive after the new drive has been installed). Hot-swappable devices do not require any additional tasks to install, such as swapping a power supply in the system.