A presentation on the DPF

1
A presentation on the DPF
The Distributed Processing Framework

• CS 590L - Santhosh

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The DPF objective

• To provide for remoting of components at run-time
• To provide for a minimal mobile agent framework

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Remoting components at run-time

• Remoting a component At the conceptual level
• Component migration may be simulated by
• Persisting current state of the component
• Remoting state storage information
• Remoting component source
• Instantiating agent on the remote machine
• Reviving agent state
• The DPF must provide for remoting an agents
  source, instantiating a remote agent, reviving
  the agents state, and transferring control back
  to the agent on the remote host

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DPF Entities and Interfaces

• Components and interfaces
• StationManager (IStationManager) - exe
• Station (IStation) - exe
• Agent (IAgent) dll
• Each component must adhere to well-defined,
  standardized interfaces in order to work with the
  framework

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DPF Entities and Interfaces

• Interfaces
• IStation
• TransferAgentToRemoteHost(in BSTR
  szRemoteHostName, in BSTR bszComponentDllFileNam
  e, in BSTR bszAgentStateSTGFileName, in CLSID
  clsidOfAgent)
• RegisterDllComponent(in BSTR bszDllpath)
• StartAndRunAgent()
• CopyAgentStateFromShare(in BSTR
  bszAgentStateSTGFileName)
• CopyAgentSourceFromShare(in BSTR
  bszComponentDllFileName)
• IAgent
• RunAgent (in IStation pIStation)
• IPersist, IPersistStream, IPersistStreamInit
• Load(IStream pStm)
• Save(IStream pStm, BOOL fClearDirty)
• IsDirty(void)
• GetSizeMax(ULARGE_INTEGER pcbSize)
• InitNew(void)
• GetClassID(CLSID pClassID)

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Working of the DPF prototype

• A high level algorithm
• Client-
• Create Agent component DLL
• Instantiate StationManager
• Pass to StationManager Agent IID and CLSID
• StationManager
• Instantiate Station (Load Station DLL into
  memory)
• Pass to Station Agent IID and CLSID
• Station
• Register Agent component
• Instantiate Agent (Load Agent DLL into memory)
• Call RunAgent method of Agent
• Upon TransferAgent request, create new instance
  of Station on remote machine. Send Agent DLL and
  Agent STG files
• Remote Station instantiates Agent on remote
  machine
• Remote Agent retrieves persisted state and
  continues execution
• Agent
• Execute Agent specific code (RunAgent method)
• Persist state with methods implemented by
  Ipersist
• On transfer request call TransferAgent method of
  Station

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Working of the DPF prototype

• End user calls StationManager.exe with path to
  Agent.dll
• StationManager calls Station.exe
• Station registers Agent.dll
• Station creates Agent
• Agent executes and invokes IStation-gtTransferAgent
  ToRemoteHost() when it wants to move
• Station invokes Remoting procedure

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DPF Prototype The next step

• Implementing a singleton DPF Station component
• Providing for persisting of basic byte stream
  (framework handles persistence)
• Comparative analysis of an Agent based scenario
  vs. a non-Agent based scenario