11-12-2007 06:38 AM
All Seagate drives ending with "LC" are SCA drives. The Seagate drive models which end with the letters "LC" support "hot swap" cabinets and are not designed for internal installation into a desktop or workstation.
For further details, please review the following Seagate web pages:
SCA Interface and Adapters
Interpreting Seagate Disc Drive Model Numbers
There are adapters which allow the use of 80 pin drives. However, there are many reasons why this is not an approved or recommended procedure.
Adapting contemporary SCA ( Single Connector Attachment ) drives will restrict the data transfer rates and reduce the life of the drives by forcing " resends" . The resends are resultant from corrupted data, the drive has to be seeking continually to accommodate the resend requests.
The adapters create the electrical effect of inductive reactance which causes cross-talk to occur, the cross-talk resulting from alternating constructive and destructive signal additions. The adapters also create an inductive impedance by having two sets of connectors sandwiched so closely.
Inductive impedance is not the only undesirable electrical effect the adapter will create, there is additionally the physics of capacitive coupling. Capacitive coupling to a floating ground state contributes to signal reflection due to an electrical hysteresis and results in signal reflections. Signal reflections and cross talk will result in data corruption.
The consequence is a retry. Corrupt data will generate retrys resulting from the cross-talk and signal reflections which corrupt the data by having a bit jump across from one wire to a neighboring wire in the data cable. This will cause the controller to reject the data packets and request additional resends. The continual head travel will effectively result in a shortened drive life.
The use of adapters may allow 80 pin SCSI drives to be used as 68 pin drives, even if in a corrupted state. There are many manufacturers of these 80 to 68 adapters and caution should be used to limit purchases to those adapters which have proper stub termination.
The " stub termination" references a manufacturing technique that ties the eliminated data lines and the eliminated return lines to a common ground. Many cheaper adapters fail to do this and the result is stub ends that work as aerials and attenuate signals ( noise ) into the data transmissions.
The downside of the use of adapters, is even with a quality adapter there is going is be data corruption. After four resends the resend function is overridden and the next data command is sent.
We recommend upgrading as the transfer rate and negative aspects of the incorrect interface doesn't justify its' use.