Manx SA7x Guía de instalación descargar pdf (Pagina 208)

8.2 Troubleshooting the Magazine Tape Subsystem

Table 8–4 (Cont.) Common Failures, Causes, and Fixes

Symptom Probable Cause Possible Fix

Cartridge stuck in drive with

tape on take up reel

Hard drive error Attempt recovery by

pressing the unload

button.

Drive leader runaway Mispositioned cartridge

leader

Inspect cartridge

leader for correct

position. Retire

cartridge from use

if leader cannot be

repositioned.

8.2.5 Soft Error Rates

None of the cartridges contain perfect tape. All tapes contain some number

of dropouts. Although these are imperfections in the tape, the tape is not

considered to be defective. The hardware and software are designed to deal

with these known imperfections. Dropout testing is performed on samples of

media by our vendors and meet all of the speciﬁcations of Digital Equipment

Corporation.

There are many variables that can cause soft errors. In fact, errors are

somewhat of a misnomer since soft errors are considered to be events. In the

case of soft errors, it is important to realize that no data has been lost. For a

write, the data is rewritten. For a read, retries are performed.

Some of the variables that create soft errors are:

• Media dropouts

• Temperature of media (not acclimatized)

• System bus activity

• Applications

• Head wear

• Contamination

Changes in soft error rates for any particular drive and cartridge are more

signiﬁcant than any absolute number of soft errors. This is due to the variables

described above.

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Manx SA7x Guía de instalación Pagina 208