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

HMP
       Host Monitoring Protocol (RFC 869)


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

hybrid multiprocessing
HMP

    (HMP) The kind of multitasking which OS/2
   supports.  HMP provides some elements of symmetric
   multiprocessing, using add-on IBM software called MP/2.
   OS/2 SMP was planned for release in late 1993.

   (1995-03-19)