Installation Guide

28 Troubleshooting and Diagnostics
Causes of the Media Warning Message
The Media Warning message appears whenever the drive has determined that low level error performance
has degraded to a point where drive head cleaning is absolutely required. It does this by counting the number
of C3 (soft) errors as well as the RAW (Read After Write) errors over a number of Mbytes. When a
predetermined error rate threshold is reached, the drive displays the warning. When a tape is loaded, it may
take several minutes for the indication to come on because the drive will wait for a specific number of bytes
to be written. A hard (non-recoverable) error will cause the warning to be displayed immediately.
The most common causes of the Media Warning Message, in order of highest rate of occurrence, is listed
below:
• Dirty ("Stained") heads.
• A cleaning cycle must be executed to clear this indication.
• Bad environment.
• Data errors result from a number of factors, each of which subtract from the margin between good data
recovery and an error. Electrical or magnetic interference can decrease this margin. High levels of dust
contamination, high humidity, and heat can also be significant factors.
• Worn heads.
• The tape heads will eventually wear out causing the time between cleanings to get shorter and shorter.
Tape head failure is usually predicted at about 12% of the 200,000-hour MTBF rating.
• Defective drive.
Drive amplifier settings could be off, causing error rate degradation. The drive could simply have failed.
High Humidity
If the drive detects high humidity, a warning is displayed by the drive LEDs. Any commands that are
currently being executed are aborted, and any commands that access the tape are rejected with a CHECK
CONDITION. In addition, the tape is unthreaded to prevent tape and head damage. As soon as the drive
detects that humidity is at an acceptable level, it will once again respond to commands that access the tape.
To minimize the chance of condensation, please observe the following guidelines:
p If you expose cartridges to temperatures outside the operating limits (5-40°C/40-113°F), stabilize them
before you use them. To do this, leave the cartridges in the operating temperature for a minimum of two
hours.
p Avoid temperature problems by ensuring that the ventilator slots at the front of the drive and the grille
on the side of the chassis are not obstructed so that the drive has adequate ventilation.
p Position the drive where the temperature is relatively stable, for example, away from open windows, fan
heaters, and doors.
p Avoid leaving cartridges in severe temperature conditions, for example, in a car standing in bright
sunlight.
p Avoid transferring data (reading from and writing to cartridges) when the temperature is changing by
more than 10°C per hour.