dr, drmach - dynamic reconfiguration driver
dr
drmach
The dynamic reconfiguration (DR) driver consists of a platform-independent
  driver and a platform-specific module. The DR driver uses standard features of
  the Solaris operating environment whenever possible to control DR operations
  and calls the platform specific module as needed. The DR driver creates minor
  nodes in the file system that serve as attachment points for DR operations.
The DR driver provides a pseudo-driver interface to sequence attach and detach
  operations on system boards using file system entry points referred to as
  "attachment points." The attachment point form depends on the
  platform.
ioctl(2), 
libcfgadm(3LIB)