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OMI - Connect

Draft MDC Standard

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5.4.1 Connect

(Operation type 1) The fields of the connect request and their sequence shall be:

  1. Major version: <SI> the major version of the OMI protocol supported by the agent. This document defines major version 2. If the agent supports multiple versions, it shall send connect requests for each until the server accepts a major version.
  2. Minor version: <SI> the minor version of the OMI protocol supported by the agent. This document defines minor version 0. The agent should send the highest minor version it supports.
  3. Min/max values: <LI> The next 10 fields are 5 pairs of minimum and maximum lengths for global values, individual subscripts, global references, total message length, and limit on requests outstanding. These values represent the minimum acceptable to the agent and the maximum that can be processed by the agent.
    The server shall compare these values with its own limits and shall return either the largest value possible or, if the agent’s lengths are not within its bounds, an error condition.
    Agents shall send minimum values that accommodate the portability requirements of ANSI/MDC X11.1. Maximum values may be as high as the agent can support. For example, an agent that supports global value lengths of 510 bytes would send min = 255 and max = 510. A server with maximum global value length of 255 would respond with a maximum of 255. The agent should thereafter return a maximum length error to any client that sets global values longer than 255.
    Minimum and maximum values for the limit on requests outstanding shall both equal 1. Larger values allow for higher performance in extensions and future versions of the protocol.
  4. 8 bit: <SI> The 8 bit flag indicates whether the agent supports 8 bit bytes for global values and subscripts. 0 means that only 7 bit values are valid; 1 means that all 8 bit values are valid.
    NOTE – This flag does not affect the overall protocol, which shall transmit 8 bit characters.
  5. Character translation: <SI> governs the character set that the agent proposes for all strings except those governed by the character translation flag in the global reference and those explicitly specified in this standard. See 4.4 and 5.3.3. 0 selects the extended M[UMPS] character set profile. 1 selects the un-translated character set of the server. All other values are reserved.
  6. Implementation identification: <SS> identifies the implementation of M[UMPS] or other software that is running on the agent. This field is for information only and does not affect the operation of the protocol. Implementers shall register their implementation identifiers with the MUMPS Development Committee, the sponsor of ANSI/MDC X11.2, to avoid duplication. Implementers who do not wish to register an identification may use an empty string.
  7. Agent name: <SS> the OMI node name assigned to the agent’s node, used along with the agent’s password to authenticate that the agent is not an impersonator.
  8. Agent password: <SS> a password assigned by the network manager, used by the server for authentication.
  9. Server name: <SS> the OMI node name assigned to the server’s node with which the agent wishes to establish a session. This name may or may not relate to the names used to establish the circuit in the underlying protocol.
  10. Extension count: <SI> the count of extension numbers that follow.
  11. Extension number(s): 0 or more fields contain extension numbers that the agent proposes to use in this session. These extension numbers are assigned by the MUMPS Development Committee and need not relate directly to operation classes. See 4.12.
<SI>
Major
Ver		 <SI>
Minor
Ver		 <LI>
Min		 <LI>
Max		 <LI>
Min		 <LI>
Max		 <LI>
Min		 <LI>
Max		 <LI>
Min		 <LI>
Max		 <LI>
Min		 <LI>
Max		 <SI>
 
8 bit
Value Subscript Reference Message Outstand

<SI>
Char
Trans		 <SS> <SS> <SS> <SS> <SI>
Ext
Count		 <LI>
1st
Ext#		 <LI>
2nd
Ext#
<SI> Implem
ID		 <SI> Agent
Name		 <SI> Agent
Passwrd		 <SI> Server
Name

Figure 12 – Connect request

The fields of the connect response and their sequence shall be:

  1. Major version: <SI> the major version of the OMI protocol supported by the server.
  2. Minor version: <SI> the minor version of the OMI protocol supported by the server. The server shall send the highest minor version it supports that is not greater than the agent’s minor version.
  3. Max values: <LI> The next 5 fields are the maximum lengths for global values, individual subscripts, global references, total message length, and limit on requests outstanding. These values shall equal the largest acceptable to the server but shall not exceed the maxima proposed by the agent in the connect request. If the server cannot satisfy this constraint, then it shall return an error condition.
    NOTE – When the agent requests minima that meet the portability requirements of ANSI/MDC X11.1, the server should be able to accept those values. Failure to agree means that 1 of the parties does not conform to the OMI protocol.
    The limit on requests outstanding shall equal 1. Larger values allow for higher performance in extensions and future versions of the protocol.
  4. 8 bit: <SI> The 8 bit flag indicates whether the server agrees to use 8 bit bytes for global values and subscripts. 0 means that only 7 bit values are valid; 1 means that all 8 bit values are valid.
  5. Character translation: <SI> indicates the server’s selection of the character set to be used during the session for all strings except those governed by the character translation flag in the global reference and those explicitly specified in this standard. See 4.4 and 5.3.3. 0 selects the extended M[UMPS] character set profile. 1 selects the un-translated character set of the server. All other values are reserved.
  6. Implementation identifier: <SS> identifies the implementation of M[UMPS] or other software that is running on the server. See the corresponding field in the connect request.
  7. Server name: <SS> the OMI node name assigned to this server’s node.
  8. Server password: <SS> a password assigned by the network manager, used by the agent for authentication.
  9. Extension count: <SI> the count of extension numbers that follow.
  10. Extension number(s): <LI> 0 or more fields contain extension numbers that the server agrees to use in this session. Only extensions proposed by the agent shall be returned. These extension numbers are assigned by the MUMPS Development Committee and need not relate directly to operation classes. See 4.12.
<SI>
Major
Version		 <SI>
Minor
Version		 <LI>
Max
Value		 <LI>
Max
Sub		 <LI>
Max
Ref		 <LI>
Max
Mes		 <LI>
Max
Out		 <SI>
8 bit		 <LI>
Char
Trans

<SS> <SS> <SS> <SI>
Ext
Count		 <LI>
1st
Ext#		 <LI>
2nd
Ext#
<SI> implemen
ID		 <SI> Server
Name		 <SI> Server
Password

Figure 13 – Connect response

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Copyright © Standard Documents; 1977-2024 MUMPS Development Committee;
Copyright © Examples: 1995-2024 Ed de Moel;
Copyright © Annotations: 2003-2008 Jacquard Systems Research
Copyright © Annotations: 2008-2024 Ed de Moel.

Some specifications are "approved for inclusion in a future standard". Note that the MUMPS Development Committee cannot guarantee that such future standards will indeed be published.

This page most recently updated on 14-Nov-2023, 21:48:39.

For comments, contact Ed de Moel (demoel@jacquardsystems.com)