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Annotation of OpenXM/doc/issac2000/ox-messages.tex, Revision 1.4

1.4     ! ohara       1: %%$OpenXM: OpenXM/doc/issac2000/ox-messages.tex,v 1.3 2000/01/11 05:35:48 noro Exp $
1.1       takayama    2:
1.4     ! ohara       3: \section{OX messages}
1.1       takayama    4:
                      5: An OX message for TCP/IP is a byte stream consisting of
                      6: a header and a body.
                      7: \begin{center}
                      8: \begin{tabular}{|c|c|}
                      9: \hline
                     10: Header & \hspace{10mm} Body \hspace{10mm} \\
                     11: \hline
                     12: \end{tabular}
                     13: \end{center}
                     14: The header consists of two signed 32 bit integers.
                     15: The first one is an OX tag
                     16: and the second one is a serial number of the OX message.
                     17: Negative numbers are expressed by the two's complement.
                     18: Several byte orders including the network byte order
                     19: are allowed and the byte order is determined as a part of
1.3       noro       20: the establishment of a connection. See Section \ref{secsession}.
1.1       takayama   21:
1.4     ! ohara      22: The OX messages are classified into three types:
1.1       takayama   23: DATA, COMMAND, and others.
                     24: We have the following main tags for the OX messages.
                     25: \begin{verbatim}
                     26: #define        OX_COMMAND               513  // COMMAND
                     27: #define        OX_DATA                  514  // DATA
                     28: #define OX_SYNC_BALL             515  // others
                     29: #define OX_DATA_WITH_LENGTH      521  // DATA
                     30: #define OX_DATA_OPENMATH_XML     523  // DATA
                     31: #define OX_DATA_OPENMATH_BINARY  524  // DATA
                     32: #define OX_DATA_MP               525  // DATA
                     33: \end{verbatim}
                     34:
                     35: New OX tags may be added.
                     36: The new tag should be classified into DATA or COMMAND.
1.2       takayama   37: For example, \verb+ OX_DATA_ASIR_LOCAL_BINARY +  was added a few month ago
                     38: to send internal serialized objects of asir via the OpenXM protocol.
1.4     ! ohara      39: This is a tag classified to DATA.
        !            40: See the web page of OpenXM to add a new tag.
1.1       takayama   41:
                     42: In OpenXM, a distributed computation is done as follows:
                     43: \begin{enumerate}
                     44: \item A client requests something to a server.
1.3       noro       45: \item The server does some work according to the request.
1.1       takayama   46: \item The client requests to send data to the server.
                     47: \item The server sends the data to the client and the client gets the data.
                     48: \end{enumerate}
1.4     ! ohara      49: The server is a stack machine. (see Section~\ref{sec:ox-stackmachines}
        !            50: for detail)
1.2       takayama   51: That is {\it OX data} message sent by the client
1.1       takayama   52: are pushed to the stack of the server.
1.4     ! ohara      53: If the server gets an {\it OX command} message, then the server extract
        !            54: a stack machine code in the OX command message and interpret the code.
        !            55: For example, in case of SM\_executeFunction, some data are popped from
        !            56: the stack and they are used as arguments of a function call.
        !            57:
        !            58: We explain an implementation of handling OX messages.
        !            59: For example, the asir command {\tt ox\_push\_cmo(P,1)}
        !            60: (push integer $1$ to the server $P$)
1.1       takayama   61: sends an OX data message
1.4     ! ohara      62: {\tt (OX\_DATA,(CMO\_ZZ,1))} to the server $P$.
1.1       takayama   63: Here,
                     64: OX\_DATA stands for OX\_DATA header and
1.4     ! ohara      65: {\tt (CMO\_ZZ,1)} is a body standing for $1$ expressed
1.2       takayama   66: in the CMO data encoding format.
1.4     ! ohara      67: The server tranlates $(CMO\_ZZ, 1)$ to its own internal object fotrmat
        !            68: for integers and pushs the object to the stack.
1.1       takayama   69:
1.4     ! ohara      70: An OpenXM client admit that its own command sends some OX messages
        !            71: sequentially at once.
1.1       takayama   72:
1.4     ! ohara      73: For example, the asir command
        !            74: {\tt ox\_execute\_string(P, "Print[x+y]")} sends an OX data message
        !            75: {\tt (OX\_DATA, (CMO\_STRING, "Print[x+y]"))} and an OX command message
        !            76: {\tt (OX\_COMMAND, (SM\_executeStringByLocalParser))} to an OpenXM
        !            77: server.