Installation guide

The information DDR provides about SCSI devices is needed by SCSI
drivers. You can supply this information using DDR when you add new
SCSI devices to the system, or you can use the /sys/data/cam_data.c
data file and static configuration methods. The information provided by
DDR and the cam_data.c file have the same objectives. When compared to
the static method of providing SCSI device information, DDR minimizes the
amount of information that is supplied by the device driver or subsystem to
the operating system and maximizes the amount of information that is
supplied by the device itself or by defaults specified in the DDR databases.
6.1.1 Conforming to Standards
Devices you add to the system should conform to the SCSI-2 standard, as
specified in SCSI-2, Small Computer System Interface-2 (X3.131-1994).If
your devices do not comply with the standard, or if they require exceptions
from the standard, you store information about these differences in the
DDR database. If the devices comply with the standard, there is usually no
need to modify the database.
6.1.2 Understanding DDR Messages
Following are the most common DDR message categories and the action, if
any, that you should take.
• Console messages are displayed during the boot sequence.
Frequently, these messages indicate that the kernel cannot read the
DDR database. This error occurs when the system’s firmware is not at
the proper revision level. Upgrade to the correct revision level of the
firmware.
• Console messages warn about corrupted entries in the database.
Recompile and regenerate the database.
• Runtime messages generally indicate syntax errors that are produced
by the ddr_config compiler. The compiler runs when you use the
−c
option to the ddr_config utility and does not produce an output
database until all syntax errors have been corrected.
6.1.3 Getting Help with ddr_config Options
Use the −h option to the ddr_config command to display help on
command options.
6–2 Administering Devices with Dynamic Device Recognition