INT 61 - Banyan VINES - "Sosock" - OPEN COMMUNICATIONS SOCKET
        AX = 0001h subfn 0001h
        DS:DX -> communications control block (function 0001h)
Return: AX = status (see below)
Note:   Banyan can use any interrupt from 60h through 66h.  The Banyan
          interrupt handler is identified by the string "BANV" in the four
          bytes immediately preceding the interrupt handler
SeeAlso: AX=0001h/SF=0002h,AX=0001h/SF=0008h,INT 15/AX=DE2Eh

Values for status:
 0000h  successful
 0001h  service not installed
 0002h  invalid service ID
 0098h  resource already in use
 009Eh  address family does not exist
 009Fh  socket type does not exist
 00A0h  protocol does not exist
 00A1h  no more sockets available
 00A2h  no more buffer space available

Format of control block:
Offset  Size    Description
 00h    WORD    0001h
 02h    WORD    pointer to argument block
 04h    WORD    error return code
 06h  4 BYTEs   reserved

Format of argument block:
Offset  Size    Description
 00h    WORD    pointer to 2-byte buffer for socket identifier
 02h    WORD    address family
                0003h Banyan
 04h    WORD    socket type
                in address family 0003h
                    0001h IPC socket
                    0002h SPP socket
 06h    WORD    protocol number
                FFFFh default
 08h    WORD    pointer to 16-byte buffer for socket address
 0Ah    WORD    local port number
                0000h if service should assign transient port number
                0001h to 01FFh well-known port number (assigned by Banyan)

Format of IPC port:
Offset  Size    Description
 00h    WORD    address family (always 0003h for Banyan ports)
 04h  4 BYTEs   network number (server's serial number)
 06h    WORD    subnet number  (0001h = server, 8000h-FFFEh = PC)
 08h    WORD    port ID (0001h-01FFh for "well-known" ports)
 0Ah    BYTE    hop count
 0Bh  5 BYTEs   filler

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