INT 2F - DBLSPACE.BIN - "GetVersion" - INSTALLATION CHECK
        AX = 4A11h
        BX = 0000h
Return: AX = 0000h (successful)
        BX = 444Dh ("DM")
        CL = first drive letter used by DBLSPACE (0=A:)
        CH = number of drive letters used by DBLSPACE
        DX = internal DBLSPACE.BIN version number (bits 14-0)
                bit 15 set if DBLSPACE.BIN has not yet been relocated to final
                position in memory (i.e. DBLSPACE.SYS /MOVE)
Program: DBLSPACE.BIN is the resident driver for DoubleSpace, the
          disk-compression software bundled with MS-DOS 6.0
SeeAlso: AX=4A11h/BX=0001h,AX=4A11h/BX=0002h,AX=4A11h/BX=0003h
SeeAlso: AX=4A11h/BX=0005h,AX=4A11h/BX=0007h,AX=4A11h/BX=FFFFh
SeeAlso: INT 21/AX=4404h"DBLSPACE"

.