A 3592E05 drive using the dual ports  is connected as shown:-

The problem encountered was that each time a read job was fired to the tapedrive from the workstation, the tape used to rewind itself after copying a few files. Upon removing the connection to the SAN switch to the tape drive, the copy job completed without any problem.

Diagnosis : RSCN (Redundant State Change Notification) propogating in the SAN was rewinding the tape drive.The problem was due to addition of tape drive to the the SAN without 'zoning'. Zoning restricts such 'broadcast' events.

Solution: Opened the SAN switch through Cisco works, no zone found between the server and tape drive. Created a zone between the server and tape drive and reconnected the cables.   Fired the copy job and everything worked as it should work.

Lesson: Don't put orphaned tape drives on the SAN.