mode_sense ioctl failed i o error

Step 1.
What is the method of connection from the Media Server to the Tape Drives (SAN, SCSI, iSCSI, other?)

Step 2.
Assuming SAN connectivity, have you verified that the HBA is still logged into the fabric?

Step 3.
Have you verified that the HBA is zoned to see the tape drives, and that the zone is active?

Step 4.
Have you verified that the Operating System (Windows) can see the tape devices, in Device Manager?

Step 5.
Are the tape drives in a robotic library?
Does the OS see the library (Medium Changer in the Device Manager)?

Step 6.
Can the Media Server communicate over the data path to the tape drives?
Assuming the default location of the NetBackup Install:
"C:\Program Files\VERITAS\Volmgr\bin\scan.exe"
How many tape drives are listed
Do they report the following details:
Device Name, Host, Port, Target, LUN, Serial Number, Inquiry String
Does the Library report in the scan output
Does it have Drive locations with Serial numbers?

Step 7.
Delete the existing drive mapping for the tape drives from tpconfig.

Step 8.
run tpautoconf -a
"C:\Program Files\VERITAS\Volmgr\bin\tpautoconf.exe -a"

Step 9.
stop and restart ltid
"C:\Program Files\VERITAS\Volmgr\bin\stopltid.exe"
"C:\Program Files\VERITAS\Volmgr\bin\ltid.exe"

Step 10.
run robtest
"C:\Program Files\VERITAS\Volmgr\bin\robtest.exe"
select your robot from the list
if the mode sense still does not work, call support.
if the mode sense works, try sensing the drives
s d
if you see your list of tape drives, quit robetest
q
q
you should be back at a command prompt

Step 11.
Check tpconfig -d and vmoprcmd -d

Step 12.
try a backup