Hot swapping
However, it is common for mid to high-end servers and mainframes to feature hot-swappable capability for hardware components, such as CPU, memory, PCIe, SATA and SAS drives.
An example of hot swapping is the express ability to pull a Universal Serial Bus (USB) peripheral device, such as a thumb drive, external hard disk drive (HDD), mouse, keyboard, or printer out of a computer's USB slot or peripheral hub without ejecting it first.
Dedicated digital cameras and camcorders usually have readily accessible memory card and battery compartments for quick changing with only minimal interruption of operation.
Hot swapping may be used to add or remove peripherals or components, to allow a device to synchronize data with a computer, and to replace faulty modules without interrupting equipment operation.
Important cards such as disk controllers or host adapters may be designed with redundant paths in order for these to be replaceable in case of failure without necessitating interruption of associated computer system operation.
Pins of the same nominal length do not necessarily make contact at exactly the same time due to mechanical tolerances, and angling of the connector when inserted.
Specialized hot-plug power connector pins are now commercially available with repeatable DC current interruption ratings of up to 16 A.
Two sense pins are located in opposite corners so that fully seated detection is confirmed only when both of them are in contact with the slot.
ESD effects can be reduced by careful design of the mechanical package around the hot-swap component, perhaps by coating it with a thin film of conductive material.
CMOS buffer devices are now available with specialized inputs and outputs that minimize disturbance of bussed signals during the hot-swap operation.
In the mid-1990s, several radio transmitter manufactures in the US started offering swappable high power RF transistor modules.
Hot swapping can also refer to the ability to alter the running code of a program without needing to interrupt its execution.
Only a few programming languages support hot swapping natively, including Pike, Lisp, Erlang, Smalltalk, Visual Basic 6 (not VB.NET), Java and most recently Elm[8] and Elixir.
[9] Hot swapping is the central method in live coding, where programming is an integral part of the runtime process.
In general, all programming languages used in live coding, such as SuperCollider, TidalCycles, or Extempore support hot swapping.
This does not apply to markup and programming languages such as HTML and PHP respectively, in the general case, as these files are normally reinterpreted on each use by default.
Hot swapping also facilitates developing systems where large amounts of data are being processed, as in entire genomes in bioinformatics algorithms.
