ADIC DS9000 Series - Manual (Page 46)

34 Troubleshooting and Diagnostics
Use Cleaning Tape LED
If an excessive number of read-after-write errors are detected during normal operation of the DS9000 Series unit, the
Use Cleaning Tape LED will be turned on by the drive.
Usually, the Use Cleaning Tape LED is turned on by the drive because of a dirty head, so the head should be
cleaned (see Cleaning the Tape Head in Chapter 3, earlier in this manual) and the operation tried again.
If the Use Cleaning Tape LED is again turned on and this appears that to be a cartridge rather than a drive
problem, perform a complete backup from the source drive with a different cartridge, if necessary. Then discard the
old cartridge. If unsure of the problem source, call ADIC Technical Assistance Center. For additional information
see the section, When Assistance is Required, later in this chapter.
The Use Cleaning Tape LED is normally turned off by executing a cleaning cycle or by cycling power to the
DS9000 Series.
Why the Use Cleaning Tape LED Gets Turned ON
The Use Cleaning Tape LED will be turned on whenever the drives determine that low level error performance
has degraded to a point where drive head cleaning is necessary. 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. Some drives display the warning after a specified number of
hours of tape motion have been logged. 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 reasons the Use Cleaning Tape LED illuminates are listed below, in order of highest rate of
occurrence:
N
Dirty ("Stained") heads.
A cleaning cycle must be executed to clear this indication.
N
Worn tape.
DLTTape IV cartridges are rated at 1,000,000 passes. Applications that overwrite small blocks of data
cause "shoe shining" of the tape against the head and will reach the 1,000,000 passes sooner than
might be expected.
N
Harmful 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 magnetic can decrease this margin.
High levels of dust contamination, high humidity, and heat can also be significant factors.
Example
Placing a CRT monitor on top of, or directly next to, a DS9000 Series should
always be avoided.
N
Worn heads.
The tape heads will eventually wear out causing the time between cleanings to get shorter and shorter.