INT 21 - Novell NetWare - MESSAGE SERVICES - SEND PERSONAL MESSAGE
        AH = E1h subfn 04h
        DS:SI -> request buffer (see below)
        ES:DI -> reply buffer (see below)
Return: AL = status
            00h successful
            FEh I/O error or out of dynamic workspace
Notes:  this function is supported by NetWare 4.0+ and Advanced NetWare 1.0+
        message pipes use CPU time on the file server; IPX, SPX, or NetBIOS
          connections should be used for peer-to-peer communications as these
          protocols do not use file server time
SeeAlso: AH=E1h/SF=05h,AH=E1h/SF=06h,AH=E1h/SF=08h

Format of request buffer:
Offset  Size    Description
 00h    WORD    length of following data (max E5h)
 02h    BYTE    04h (subfunction "Send Personal Message")
 03h    BYTE    number of connections (01h-64h)
 04h  N BYTEs   list of connections to receive broadcast message
        BYTE    length of message (01h-7Eh)
      N BYTEs   message (no control characters or characters > 7Eh)

Format of reply buffer:
Offset  Size    Description
 00h    WORD    (call) size of following results buffer (max 65h)
 02h    BYTE    number of connections
 03h  N BYTEs   list of per-connection results
                00h successful
                FCh message rejected because queue is full (contains 6 msgs)
                FDh incomplete pipe
                FFh failed