SimpleTech ZeusIOPS User Manual

Zeus

IOPS

 3.5-Inch Fibre Channel Solid State Drive Product Manual Rev. 1.0

63

For host systems that are not DMP capable, having two paths from the same host machine to the 
same drive can cause problems. For example, if the two channels are connected to the same host 
machine when running an operating system that does not support DMP, two separate disks will be 
reported by the operating system even though both reported disks are the same physical storage. 
This can cause corruption to occur if the drive is subsequently accessed down both channels. See 
Single Channel Mode for Early Revision Drives on page 66.

To accommodate both DMP and non-DMP capable systems, the SSD can be configured so that it 
only operates (and is only visible) down one of the two channels. This feature is most likely to be used 
on systems that do not support DMP but where the drives in the same JBOD chassis are to be 
mirrored. Enabling just the A channel for the main drive and the B channel on the mirror drive will 
cause both drives to be visible via separate host channels, thereby preventing any single point of 
failure.

The feature is enabled by inserting a 2mm option jumper onto the two pins marked as JP1 on the 
underside of the drive. Please note that jumper JP1 is located on the 10-way right-angled connector 
that also serves as a test connector during manufacture. The drive will require power cycling after 
JP1 is installed or removed. When this feature is enabled, the LSB of the SELECT_ID determines the 
port that the drive will use. If the SELECT_ID is even, then port A is used. If the SELECT_ID is odd, 
then port B is used.

Under certain conditions, the SSD will drive the Fault LED Out (fault signal) on the SCA-2 interface. 
In most system configurations, this will normally be connected to an LED on the chassis that is visible 
to the user.