Installation guide

6
Administering Devices with Dynamic
Device Recognition
This chapter describes the Dynamic Device Recognition (DDR) database,
which you use to administer devices in the SCSI/CAM I/O subsystem. It
explains how you use the ddr_config utility to manage the DDR database
on your system. This chapter introduces DDR, then describes how you use
the ddr_config utility to:
• Add SCSI devices to the DDR database
• Convert a customized cam_data.c file
This chapter also discusses adding pseudoterminals and disks and tapes
that are not SCSI devices to the operating system.
6.1 Understanding Dynamic Device Recognition
Dynamic Device Recognition is a framework for describing the operating
parameters and characteristics of SCSI devices to the SCSI CAM I/O
subsystem. You can use DDR to include new and changed SCSI devices into
your environment without having to reboot the operating system. You do
not disrupt user services and processes, as happens with static methods of
device recognition.
Beginning with Tru64 UNIX Version 4.0, DDR is preferred over the
current, static method for recognizing SCSI devices. The current, static
method, as described in Chapter 5, is to edit SCSI device customizations
into the /sys/data/cam_data.c data file, reconfigure the kernel, and
shut down and reboot the operating system.
_______________________ Note _______________________
Support for the static method of recognizing SCSI devices will be
retired in a future release of Tru64 UNIX .
Tru64 UNIX Version 4.0 supports both methods of recognizing SCSI
devices. Both methods can be employed on the same system, with the
restriction that the devices described by each method are exclusive to that
method (nothing is doubly-defined).
Administering Devices with Dynamic Device Recognition 6–1