Dynamic Root Disk (DRD) is an HP-UX system administration toolset
used to clone an HP-UX system image to an inactive disk for software
maintenance and recovery. The bundle name is DynRootDisk. The product name is DRD. Administrators can use DRD to reduce downtime
for system maintenance by creating an inactive clone of the booted
system, then applying patches and products to the clone. The modified
clone can then be booted at a convenient time.
The HP-UX Dynamic Root Disk web site at http://docs.hp.com/en/DRD provides a product overview, download links, documentation links,
and installation instructions.