V.E.R.A. -- Virtual Entity of Relevant Acronyms (February 2016):

DDO
       Dynamic Drive Overlay (HDD, Ontrack)


The Free On-line Dictionary of Computing (30 December 2018):

Dynamic Drive Overlay
DDO

    (DDO) Software to allow a system BIOS
   that does not support Logical Block Addressing to access
   drives larger than 528 MB.

   The alternatives are to update the system BIOS or install an
   EIDE controller card with a suitable on-board BIOS.

   Seagate
   (http://seagate.com/support/disc/drivers/discfile.shtml).

   (2001-03-18)