Hot swapping and hot plugging are terms used to separately describe the functions of replacing system components without shutting down the system. Hot swapping describes changing components without significant interruption to the system, while hot plugging describes changing or adding components which interact with the operating system.1 Both terms describe the ability to remove and replace components of a machine, usually a computer, while it is operating. For hot swapping once the appropriate software is installed on the computer, a user can plug and unplug the component without rebooting. A well-known example of this functionality is the Universal Serial Bus (USB) that allows users to add or remove peripheral components such as a mouse, keyboard, or printer.

Starting with kernel 2.4 (in January 2001), hotplugging became a standard feature of GNU/Linux. It's been backported to kernel 2.2 (for USB), and kernel 2.6 makes it available to all sysfs-adapted busses and driver classes.

In the Linux 2.6 kernel, hotplugging has been integrated with the driver model core so that any bus or class can report hotplug events when devices are added or removed.

Basic hotplug support is included in almost all current distributions of GNU/Linux, including RedHat, Debian.

Design Spec

(1) Hardware: special connectors, corner with GND Pin; consideration about power electronics;
(2) Software consideration, this is why we design code in Linux kernel about hot-swap

Example, Hotplugging is a facility that supports dynamic (re)configurationof GNU/Linux distributions by kernel reports to user mode "agent"software.

Last edited Aug 28, 2009 at 9:26 AM by webexpert21, version 1


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