StorageWorks RW551, Руководство по обслуживанию

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Medium Optical Disk (RW551/RW552) Library
6–36 EK–MOL80–SV. B01
Table 6–6 shows the error thresholds for the RWZ52 optical drive. The sector
IDs column refers to the minimum number of sector IDs that must be read cor-
rectly for the corresponding operation to be deemed successful.
The ECC level
column refers to the maximum number of bytes per interleave that require
correction in order for the corresponding operation to be deemed successful.
Table 6–6 Error Thresholds
Operation Sector Ids ECC Level
Format 2 3
Write 2 -
Erase 2 -
Verify 2 4
Read (recovered) 1 7
Read 1 8
Diagnostic Strategy
Internal Autochanger Diagnostics
The internal tests and exercisers provided by the jukebox provide diagnostic
capabilities that are not available in the standard set of SCSI autochanger
commands.
The tests are run from the control panel.
Offline Diagnostics
DOSDASS4 is a PC-based diagnostic that fully exercises both the autochanger
and the drive mechanisms.
DOSDASS4 is available from the Digital Customer
Support Center at CXO.
The SCSI Interface
As defined by ANSI (American National Standards Institute), SCSI allows up to
eight devices on the bus in any combination of computers and peripherals. The
devices can communicate with one another without control from a host
computer.
Another powerful feature is the ability of SCSI to perform arbitration. SCSI
allows the host to initiate transactions, then break communication with a device,
do something else, and re-establish communication when the device is ready.