Int 2F Fn 4A12  - Microsoft Realtime Compression Interface (mrci) - Ram-b  [k]

   AX = 4A12h
   CX = 4D52h ("MR")
   DX = 4349h ("CI")

Return: CX = 4943h ("IC") if installed
   DX = 524Dh ("RM") if installed
       ES:DI -> MRCINFO structure (see #0649 at INT 1A/AX=B001h)

Note:  this call is functionally identical to INT 1A/AX=B001h, but should be
     called first, as the latter call is used for the first, ROM-based
     MRCI server, while this call is used for RAM-based servers which
     may be partially or entirely replacing a prior server

See Also: AX=4A12h/CX=5354h,INT 1A/AX=B001h