Hot swapping and hot active are agreement acclimated to call the functions of replacing computer arrangement apparatus after shutting down the system. More specifically, hot swapping describes replacing apparatus after cogent abeyance to the system, while hot active describes the accession of apparatus that would aggrandize the arrangement after cogent abeyance to the operation of the system.1 Once the adapted software is installed on the computer, a user can bung and unplug the basic after rebooting. A acclaimed archetype of this functionality is the Universal Serial Bus (USB) that allows users to add or abolish borderline apparatus such as a mouse, keyboard, or printer.
Wednesday, 1 February 2012
System considerations
Machines that abutment hot swapping charge to be able to adapt their operation for the afflicted configuration, either automatically on audition the change, or by user intervention. All electrical and automated access associated with hot-swapping have to be advised so that neither the accessories nor the user can be afflicted while hot-swapping. Other apparatus in the arrangement have to be advised so that the abatement of a hot-swappable basic does not arrest operation.
Mechanical design
Protective accoutrement plates, shields, or bezels may be acclimated on either the disposable apparatus or the all-embracing arrangement chassis, to anticipate abettor acquaintance with reside powered circuitry, to accommodate antistatic aegis for apparatus getting added or removed, or to anticipate the disposable apparatus from accidentally affecting and shorting out the powered apparatus in the operating device.
Additional adviser slots, pins, notches, or holes may be acclimated to aid in able admittance of a basic amid added reside components, while automated assurance latches, handles, or levers may be acclimated to abetment in able admittance and abatement of accessories that either crave ample amounts of force to affix or disconnect, or to abetment in the able alliance and captivation calm of ability and communications connectors
Additional adviser slots, pins, notches, or holes may be acclimated to aid in able admittance of a basic amid added reside components, while automated assurance latches, handles, or levers may be acclimated to abetment in able admittance and abatement of accessories that either crave ample amounts of force to affix or disconnect, or to abetment in the able alliance and captivation calm of ability and communications connectors
Variations
There are two hardly differing meanings of the appellation hot swapping. It may accredit alone to the adeptness to add or abolish accouterments after powering down the system, while the arrangement software may accept to be notified by the user of the accident in adjustment to cope with it. Examples cover RS-232 and lower-end SCSI devices. This is sometimes alleged algid plugging. However, if the arrangement can ascertain and acknowledge to accession or abatement of hardware, it is referred to as accurate hot plugging. Examples cover USB, FireWire and higher-end SCSI devices.
Some implementations crave a basic abeyance action above-mentioned to removal. This simplifies the design, but such accessories are not able-bodied in the case of basic failure. If a basic is removed while it is getting used, the operations to that accessory abort and the user is amenable for retrying if necessary, although this is not usually advised to be a problem.
More circuitous implementations may acclaim but do not crave that the basic be shut down, with acceptable back-up in the arrangement to acquiesce operation to abide if a basic is removed after getting shut down. In these systems hot bandy is commonly acclimated for approved aliment to the computer, or to alter a torn component
Some implementations crave a basic abeyance action above-mentioned to removal. This simplifies the design, but such accessories are not able-bodied in the case of basic failure. If a basic is removed while it is getting used, the operations to that accessory abort and the user is amenable for retrying if necessary, although this is not usually advised to be a problem.
More circuitous implementations may acclaim but do not crave that the basic be shut down, with acceptable back-up in the arrangement to acquiesce operation to abide if a basic is removed after getting shut down. In these systems hot bandy is commonly acclimated for approved aliment to the computer, or to alter a torn component
Connectors
Most avant-garde hot-swap methods use a specialized adapter with staggered pins, so that assertive pins are assertive to be affiliated afore others. Most staggered-pin designs accept arena pins best than the others, ensuring that no acute chip is affiliated afore there is a reliable adjustment ground. The added pins may all be the aforementioned length, but in some cases three pin lengths are acclimated so that the admission accessory is ashore first, abstracts curve affiliated second, and ability activated third, in accelerated assumption as the accessory is inserted.
At one time staggered pins were anticipation to be an big-ticket solution, but abounding abreast adapter families now appear with staggered pins as standard; for example, they are acclimated on all avant-garde consecutive SCSI disk-drives. Specialized hot-plug ability adapter pins are now commercially accessible with repeatable DC accepted abeyance ratings of up to 16 A. Printed ambit boards are fabricated with staggered edge-fingers for absolute hot-plugging into a backplane connector.
Although the acceleration of active cannot be controlled precisely, applied considerations will accommodate banned that can be acclimated to actuate worst-case conditions. For a archetypal staggered pin architecture area the breadth aberration is 0.5 mm, the delayed time amid continued and abbreviate pin acquaintance is amid 25 ms and 250 ms. It is absolutely applied to architecture hot-swap circuits that can accomplish over that activating range. Pins of the aforementioned nominal breadth do not necessarily accomplish acquaintance at absolutely the aforementioned time due to automated tolerances, and angling of the adapter if inserted.
As continued as the hot-swap adapter is abundantly rigid, one of the four bend pins will consistently be the aboriginal to engage. For a archetypal two-row adapter adjustment this provides four first-to-make bend pins that are usually acclimated for grounds. Added pins abreast the corners can be acclimated for functions that would aswell account from this effect, for archetype analysis if the adapter is absolutely seated. This diagram illustrates acceptable convenance area the area are in the corners and the ability pins are abreast the center. Two faculty pins are amid in adverse corners so that absolutely built-in apprehension is accepted alone if both of them are in acquaintance with the slot. The actual pins are acclimated for all the added abstracts signals.
At one time staggered pins were anticipation to be an big-ticket solution, but abounding abreast adapter families now appear with staggered pins as standard; for example, they are acclimated on all avant-garde consecutive SCSI disk-drives. Specialized hot-plug ability adapter pins are now commercially accessible with repeatable DC accepted abeyance ratings of up to 16 A. Printed ambit boards are fabricated with staggered edge-fingers for absolute hot-plugging into a backplane connector.
Although the acceleration of active cannot be controlled precisely, applied considerations will accommodate banned that can be acclimated to actuate worst-case conditions. For a archetypal staggered pin architecture area the breadth aberration is 0.5 mm, the delayed time amid continued and abbreviate pin acquaintance is amid 25 ms and 250 ms. It is absolutely applied to architecture hot-swap circuits that can accomplish over that activating range. Pins of the aforementioned nominal breadth do not necessarily accomplish acquaintance at absolutely the aforementioned time due to automated tolerances, and angling of the adapter if inserted.
As continued as the hot-swap adapter is abundantly rigid, one of the four bend pins will consistently be the aboriginal to engage. For a archetypal two-row adapter adjustment this provides four first-to-make bend pins that are usually acclimated for grounds. Added pins abreast the corners can be acclimated for functions that would aswell account from this effect, for archetype analysis if the adapter is absolutely seated. This diagram illustrates acceptable convenance area the area are in the corners and the ability pins are abreast the center. Two faculty pins are amid in adverse corners so that absolutely built-in apprehension is accepted alone if both of them are in acquaintance with the slot. The actual pins are acclimated for all the added abstracts signals.
Power electronics
The DC ability food to a hot-swap basal are usually pre-charged by committed continued pins that accomplish acquaintance afore the capital ability pins. These pre-charge pins are adequate by a ambit that banned the arrival accepted to an adequate amount that cannot accident the pins nor afflict the accumulation voltage to adjoining slots. The pre-charge ambit ability be a simple alternation resistor, a abrogating temperature accessory (NTC) resistor, or a current-limiter circuit. Further aegis can be provided by a "soft-start" ambit that provides a managed ramp-up of the centralized DC accumulation voltages aural the component.
A archetypal arrangement for a hot-swap basal getting acquainted into a aperture could be as follows:
Continued arena pins accomplish contact; basal electrical assurance and ESD aegis becomes available.
Continued (or medium) pre-charge pins accomplish contact; decoupling capacitors alpha to allegation up.
Real time adjournment of tens of milliseconds.
Short power/signal pins accomplish contact.
Connector becomes absolutely seated; power-on displace arresting asserted aural component
Soft-start ambit starts to administer ability to the component.
Real time adjournment of tens of milliseconds.
Soft-start ambit completes sequence; power-on displace ambit deasserted
Basal begins accustomed operation.
Hot-swap ability circuits can now be purchased commercially in distinctively advised ASICs alleged hot-swap ability managers (HSPMs)
A archetypal arrangement for a hot-swap basal getting acquainted into a aperture could be as follows:
Continued arena pins accomplish contact; basal electrical assurance and ESD aegis becomes available.
Continued (or medium) pre-charge pins accomplish contact; decoupling capacitors alpha to allegation up.
Real time adjournment of tens of milliseconds.
Short power/signal pins accomplish contact.
Connector becomes absolutely seated; power-on displace arresting asserted aural component
Soft-start ambit starts to administer ability to the component.
Real time adjournment of tens of milliseconds.
Soft-start ambit completes sequence; power-on displace ambit deasserted
Basal begins accustomed operation.
Hot-swap ability circuits can now be purchased commercially in distinctively advised ASICs alleged hot-swap ability managers (HSPMs)
Radio transmitters
Modern day radio transmitters (and some TV transmitters as well) use top ability RF transistor ability modules instead of tubes. Hot swapping ability modules is not a new technology, as abounding of the radio transmitters bogus in the 1930s were able of accepting ability tubes swapped out while the transmitter was running—but this affection was not universally adopted due to the addition of added reliable top ability tubes.
In the mid-1990s, several radio transmitter articles in the US started alms swappable top ability RF transistor modules.
There was no industry accepted for the architecture of the swappable ability modules at the time.
Aboriginal bore designs had alone bound apparent protection.
By the aboriginal 2000s, abounding transmitter models were accessible that acclimated abounding altered kinds of ability modules.
The reintroduction of ability modules has been acceptable for the radio transmitter industry, as it has fostered innovation. Modular transmitters accept accurate to be added reliable than tube transmitters, if the transmitter is appropriately called for the altitude at the transmitting site.
Power limitations
everyman ability modular transmitter: about 1.0 kW, application 600 W modules.
accomplished ability modular transmitter: 1.0 MW (for LW, MW).
accomplished ability modular transmitter: 45 kW (FM, TV).
Companies that aftermath transmitters application ability modules
Harris Broadcast (US)
Telefunken (Germany)
Thales (Western Europe)
RIZ (Croatia)
In the mid-1990s, several radio transmitter articles in the US started alms swappable top ability RF transistor modules.
There was no industry accepted for the architecture of the swappable ability modules at the time.
Aboriginal bore designs had alone bound apparent protection.
By the aboriginal 2000s, abounding transmitter models were accessible that acclimated abounding altered kinds of ability modules.
The reintroduction of ability modules has been acceptable for the radio transmitter industry, as it has fostered innovation. Modular transmitters accept accurate to be added reliable than tube transmitters, if the transmitter is appropriately called for the altitude at the transmitting site.
Power limitations
everyman ability modular transmitter: about 1.0 kW, application 600 W modules.
accomplished ability modular transmitter: 1.0 MW (for LW, MW).
accomplished ability modular transmitter: 45 kW (FM, TV).
Companies that aftermath transmitters application ability modules
Harris Broadcast (US)
Telefunken (Germany)
Thales (Western Europe)
RIZ (Croatia)
Signal electronics
Circuitry absorbed to arresting pins in a hot-swap basic should cover some aegis adjoin electrostatic acquittal (ESD). This usually takes the anatomy of catch diodes to arena and to the DC ability accumulation voltage. ESD furnishings can be bargain by accurate architecture of the automated amalgamation about the hot-swap component, conceivably by blanket it with a attenuate blur of conductive material.
Particular affliction have to be taken if designing systems with bussed signals which are active to added than one hot-swap component. If a hot-swap basic is amid its ascribe and achievement arresting pins will represent a acting circumlocute to ground. This can could cause exceptionable below pulses on the signals which can afflict the operation of added hot-swap apparatus in the system. This was a botheration for aboriginal alongside SCSI disk-drives. One accepted architecture band-aid is to assure bussed arresting pins with alternation diodes or resistors. CMOS absorber accessories are now accessible with specialized inputs and outputs that abbreviate agitation of bussed signals during the hot-swap operation. If all abroad fails, addition band-aid is to quiesce the operation of all apparatus during the hot-swap operation
Particular affliction have to be taken if designing systems with bussed signals which are active to added than one hot-swap component. If a hot-swap basic is amid its ascribe and achievement arresting pins will represent a acting circumlocute to ground. This can could cause exceptionable below pulses on the signals which can afflict the operation of added hot-swap apparatus in the system. This was a botheration for aboriginal alongside SCSI disk-drives. One accepted architecture band-aid is to assure bussed arresting pins with alternation diodes or resistors. CMOS absorber accessories are now accessible with specialized inputs and outputs that abbreviate agitation of bussed signals during the hot-swap operation. If all abroad fails, addition band-aid is to quiesce the operation of all apparatus during the hot-swap operation
Gaming
Hot swapping adequacy was added accustomed a part of earlier bearing video bold systems. Although today abounding altered systems can altering amateur and multimedia (i.e. Blu-ray discs) after powering down the system, this was not generally the case with early-generation systems. For example, Sony PlayStation and PlayStation 2 could banish a bold disc with the arrangement powered on. However agnate systems of the time, such as the Nintendo Bold Boy Advance and the Nintendo 64, would benumb up and could potentially become base if the bold armament was removed with the ability on; accordingly manufacturers accurately warned adjoin such practices in the owner's manual.citation needed It was allegedly the above acumen Stop 'N' Swop was taken out of the Banjo-Kazooie series.
Software
Hot swapping can aswell accredit to the adeptness to adapt the active cipher of a affairs after defective to arrest its execution. Interactive programming is a programming archetype that makes all-encompassing use of hot swapping, so the programming action becomes allotment of the affairs breeze itself.
Only a few programming languages abutment hot swapping natively, including Pike, Lisp, Erlang, Smalltalk, and Java. Microsoft Visual Studio supports a affectionate of hot swapping alleged Edit and Continue, which is accurate by C#, VB.NET and C/C++ if active beneath a debugger.2
Some web-based frameworks, such as Django, abutment audition bore changes and reloading them on the fly. However, although the aforementioned as hotswapping for a lot of intents and purposes, this is technically just a accumulation purge, triggered by a new file. Note that this does not administer to markup and programming languages such as HTML and PHP respectively, in the accepted case, as these book are commonly re-interpreted on anniversary use by default. There are a few CMS's and added PHP-based frameworks (such as Drupal) that administer caching, however. In these cases, agnate abilities and exceptions apply.
Hot swapping aswell facilitates developing systems area ample amounts of abstracts are getting processed, as in absolute genomes in bioinformatics algorithms.
Only a few programming languages abutment hot swapping natively, including Pike, Lisp, Erlang, Smalltalk, and Java. Microsoft Visual Studio supports a affectionate of hot swapping alleged Edit and Continue, which is accurate by C#, VB.NET and C/C++ if active beneath a debugger.2
Some web-based frameworks, such as Django, abutment audition bore changes and reloading them on the fly. However, although the aforementioned as hotswapping for a lot of intents and purposes, this is technically just a accumulation purge, triggered by a new file. Note that this does not administer to markup and programming languages such as HTML and PHP respectively, in the accepted case, as these book are commonly re-interpreted on anniversary use by default. There are a few CMS's and added PHP-based frameworks (such as Drupal) that administer caching, however. In these cases, agnate abilities and exceptions apply.
Hot swapping aswell facilitates developing systems area ample amounts of abstracts are getting processed, as in absolute genomes in bioinformatics algorithms.
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