Mylex DAC960PG, Installation Manual

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Drive Organization
2-10 DAC960PG Installation Guide
If there is a mismatch, it means the device just read is an unidentified device.
If a configuration header is not in the Mylex format, the corresponding drive
is assumed to be new. Such a drive is also unidentified. If all drives
connected to the controller are unidentified, the configuration is assumed to
be new, and the controller initializes all drives as Mylex COD compatible
drives.
After the controller scans all possible drives, the header information from all
drives exists in memory. The headers are scanned to determine if there is a
valid configuration. If a configuration matches the controller’s NVRAM, it
is selected for use. If a configuration matches the NVRAM, but the sequence
number is different, then the configuration with the highest sequence number
is used. If no configuration matches the controller’s NVRAM, then the
configuration (if any) that occurs the greatest number of times is the
configuration that is used. If no valid disk configurations can be found, then
the configuration in NVRAM is used, and the Bad Data Table is cleared. A
configuration is selected from disk in all other cases, and the Bad Data Table
is read from a disk with the selected configuration.
Device Translation Table
The selected configuration becomes the basis for a device translation table.
This table is generated during the verification scan. Configuration headers
are read at this time to determine if any drive slot (target ID) changes, cable
swaps, or controller changes have occurred since the last verification scan.
At this time it is also determined whether or not any drives are missing. An
attempt is made to map any missing drives to their original slots. If the
present controller determines that the present physical configuration makes
this illegal, then the affected missing drive is assigned the first free slot
(either a non-responding slot or a slot with a non-Mylex drive in it).
If a legal configuration cannot be created, an installation abort condition
occurs, and the DAC configuration utility needs to be invoked. For more
information, refer to the DACCF Utilities Installation Guide and User
Manual.