INT 2F - SETDRVER.COM v2.10+ - INSTALLATION CHECK
        AX = E000h
Return: AX = 4A52h ("JR") if present
Program: SETDRVER is a public domain TSR by Jacob Rieper which sets the
          apparent DOS version analogously to MS-DOS SETVER
Note:   this installation check differs from the usual one of returning AL=FFh
SeeAlso: AX=E001h,INT 21/AH=52h

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