DRD-Safe Concepts for HP-UX 11i v2 and Later

3 DRD-Safe Problem Areas
Before discussing the details of how to create DRD-safe scripts and how to identify DRD-unsafe
commands in current scripts, we will take a look at the activities that are not DRD-safe and thus must
not take place in a DRD session. After we have described what types of activities are DRD-unsafe, we
will then move on to describing how to create control scripts and packages that avoid these activities
and are DRD-safe.
3.1 Process Communications
When running in the runcmd environment, commands can be executed that modify the inactive system
image. These commands can communicate with other processes that may not have been started
within the runcmd environment. These other processes may illegally change the booted system
image, or may provide information that is correct for the booted system image, but incorrect for the
inactive system image.
Following are three examples of unsafe actions related to process communications.
Example 3.1.1 – Illegal Kill: A command executed within the runcmd environment terminates a
process that was started outside of the runcmd environment. This is unsafe because the running
system expects the process to be running and could be actively communicating with that process.