HP LTO6 Tape Drive
 
HP LTO5 Tape Drive
 
IBM LTO5 Tape Drive
 
IBM LTO6 Tape Drive
 

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Goal

Solution

Oracle Confidential PARTNER - Available to partners (SUN).
Reason: Confidential for Service Personnel

Applies to:

Goal

 No LTO Fibre Light When Not Connected to Cable - This is in regard to diagnostic techniques when trying to resolve a connectivity issue

Solution

Question: It seems that in the past with various drives we were able to "see" the light from the transmit port of a device (safely with a cell phone camera).  Safely or not we were always able to visualize the transmit beam from a shortwave LED device.  I was told today that SL8500 installed LTO5/6 drives (not sure on manufacturer) do not emit a transmit signal when sitting in the tray with no cable installed. The FSE even tried splitting apart a fibre connector and only connecting the transmit cable from the switch into the receive port but that did not cause the drive to enable its own transmit LED.  However, this behavior did not seem to affect the connectivity of the drive once the cable was installed.

Answer:  This is expected behavior as follows:

• This happens only with HP drives.
• The HP LTO5/6 drives will not send a signal (ie. "Light") unless it is getting a signal from the host or switch.
• The IBM LTO5/6 drives will always give out a signal whether they are connected to something or not.
• This behavior is actually known as Open Fiber Control (OFC) handshake protocol and is meant to enhance user safety.
• The feature could be off in one device and on in another as long as "compatibility mode" is supported.
• This is provided as general information to prevent someone from trying to diagnose a symptom that is not a problem.

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