INT 50 - PC Thuis Organizer Shell - GET MEMORY HANDLE
        AX = 0015h
        BL = handle size
            00h 65536 bytes (64K)
            01h 65535 bytes (64K-1)
            02h 32768 bytes (32K)
            03h 32767 bytes (32K-1)
Return: AX = segment
Program: The PC Thuis Organizer Shell was written by John Vanderaart and
          published in the June/July 1990 issue of PC Thuis Power magazine