WHAT-IS: master versa slave

Table Of Contents

• Definition
• What is a "master" context ?
• What is a "slave" context ?
• What is a "worker" context ?

Definition

master	the leading context, the master control the slave
slave	the dependent context

In difference to the client/server link the master/slave link connect two independent parent-context in the same process or thread (e.g. node). This leading to the restriction that only one master-context can be a server-context because only one server per node is possible.

| ** client/server link ** | ** client/server link ** |

             | ** master/slave link ** |


    node-0   |          node-1         |      node-3
============ | ======================= | ========================

                         |- client1-0 -|- server3 ...
                         |
                         |                    node-4/5/6 ...
             |- server1 -|               ========================
             |           |
             |           |             |- server4 ...
  client0-0 -|           |- client1-1 -|- server5 ...
             |                         |- server6
             |
             |          node-2                node-7
             | ======================= | ========================
             |
             |- server2 -|- client2-0 -|- server7 ...

What is a "master" context ?

• the master-context is a parent-context without a child-context available.
• the master-context is a client-context or a server-context.
• the master-context is responsible to create or delete the child-context of the slave.
• the master-context is responsible to delete the parent-context of the slave.
• the link between the master-context and the slave-context is done using the libmsgque slave API: (C, C++, C#, Java, Python, Tcl, Perl, VB.NET)

What is a "slave" context ?

• the slave-context is a parent-context without a child-context available.
• the slave-context is a client-context.
• the slave-context lifetime is controlled by the master-context.
• the slave-context report all error-messages to the master-context.
• a special form of a slave-context is a worker-context

What is a "worker" context ?

• the worker-context is a slave-context using the image of the master-context self.
• the master-context have to be a server-context.
• the worker-context is create with its own constructor: (C, C++, C#, Java, Python, Tcl, Perl, VB.NET)
• the worker-context is identified by a unique integer starting with 0.