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Hot
Swap Overview
Definition of Hot Swap
The term "hot swap"
is used in the computer industry to describe physical hardware
replacement without powering off the computer. The ability to
hot swap vital components (such as hard disk drives, power supplies,
interface adapters, etc.) is an essential function of today's
fault-tolerant, mission-critical computer systems and disk arrays.
In order to hot swap drives on a SCSI bus, the host computer
or interface adapter must support this function. Most UNIX-based
systems and RAID controllers support drive hot swap, whereas
Intel-based computers and standard PC SCSI host adapters typically
do not. Apple/Macintosh computers generally support drive hot
swap with the use of available third party software.
Data Express SCSI Isolator Board
The Data Express SCSI isolator board is an upgrade attachment designed to enhance the host computer
drive hot swap function. Activated by the receiving frame key lock mechanism, the isolator board
safeguards SCSI bus operations and other devices during physical drive removal and insertion. The
isolator circuitry electronically connects or disconnects a drive from the SCSI bus during an inactivity
or "quiet" state of the bus preventing interruptions to SCSI operations.
To Isolate or Not to Isolate
The Data Express isolator
board is a SCSI bus protection device that can be applied in
most non-RAID applications that involve frequent drive removal
and insertions, as well as in RAID implementations for improved
data reliability. It is imperative to understand the use of
this device is not an absolute requirement. Most RAID controllers
provide onboard drive hot swap support and some disk drives
have "Hot Connect/Disconnect" capability, assuring
that no corruption occurs on the active SCSI bus.
StorCase recommends the use of Data Express isolator board as
a preventative measure to safeguard SCSI operations. The isolator
board is an available product option for most Data Express models.
Please contact a StorCase Sales Representative or visit the
Data Express Isolator
and Solenoid Options section of our site to find out which
Data Express models are supported.
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