Hot plug/unplug support – Western Digital WDE2170 User Manual
Page 34
Advanced Product Features
WD Enterprise WDE2170/WDE4360
RELEASED 04-08-97
4079-001045 Rev. B
26
3.19. Hot Plug/Unplug Support
The conditions for hot-plugging drives into an active SCSI bus follow:
The drive signal ground must be made before the SCSI bus signals.
Power—both +5V and +12V—cannot be applied until the SCSI bus signals are
connected.
The host(s) are not actively trying to access the inserted device.
The drive is not supplying TERMPWR to the SCSI bus.
The drive is not supplying termination to the SCSI bus.
The conditions for the removal of a device from an active SCSI bus follow:
The host(s) are not actively trying to access the device to be removed.
The drive is not supplying TERMPWR to the SCSI bus.
The drive is not supplying termination to the SCSI bus.
Power, both +5V and +12V must be removed before the SCSI bus signals are
disconnected.
The drive signal ground must be broken after the SCSI bus signals.
The SCA-2 (80-pin) connector allows for proper insertion and extraction by providing
an appropriate mechanical mating that makes the signal ground connection first upon
insertion and last upon extraction. There are also control signals that allow the proper
application of power to adhere to the insertion and extraction rules above. However, the
user must guarantee that the three rules listed below apply:
The host(s) are not actively trying to access the inserted device.
The drive is not supplying TERMPWR to the SCSI bus.
The drive is not supplying termination to the SCSI bus.