Active Backplane Vs. Passive Backplane
Gary Watson
news:38FCA59C...@fusionworld.com...
> Does anyone know the difference between RAID enclosures providing an
> active backplane versus passive backplane.
Passive backplanes do not have "active" components on them, like
terminators, bus isolators, soft-start FETs, management microprocessors,
etc. These functions, if provided, will be found on a board in the unit
other than the backplane, such as a little pluggable daughtercard.
Active backplanes if advertised as such usually have some sort of feature
which is being claimed as a benefit, such as SCSI bus isolation chips on
each slot. If the term is used by a competitor, this means that the
backplane has upon it all manner of random ICs, such as the microprocessor
which controls the front panel (the implication being that the designer was
lazy and willing to risk your downtime to save himself a little cost or
effort).
The issue at hand here is that a backplane is a difficult item to replace in
a chassis, and impossible with power on, so if any of the active components
were to fail, the system disruption could be substantial while repairs are
carried out The opposite tension is that for cost or (allegedly)
performance reasons, some designers like to put various IC's on the
backplane.
Both approaches are valid for certain types of applications. High-end RAID
systems with pluggable controllers and power supplies tend to use a passive
backplane.
--
Gary Watson
ga...@nexsan.sex (Change dot sex to dot com to reply!!!)
Nexsan Technologies Ltd.
Derby DE21 7BF ENGLAND
http://www.nexsan.com