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- ecflow_client: This executable is a command-line program; it is used for all communication with the server. This executable implements the Command Level Interface (CLI). The bulk of this functionality is also provided by the python API
- ecflow_ui: This is a specialised specialized GUI client that monitors and visualises visualizes the node tree hierarchy. Based on QT.
- ecflow_server: This executable is the server. It is responsible for scheduling the jobs and responding to ecflow_client requests.
- ecflow.so: Python interface These shared libraries provide the python API for creating the suite definition and communication with the server.
ecFlow runs as a server receiving requests from clients. CLI, GUI, and the suite jobs are the clients. Communication is based on TCP/IP. Note that ecFlow is a scheduler and is not a queuing system such as NQS, SGE, Load leveller leveler, or PBS. However, it can submit to queuing systems.
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For almost three decades ECMWF used SMS (Supervisor Monitoring Scheduler) package to control the work flow workflow for the Centre's operational models and systems. Written at ECMWF, it allows the design, submission, and monitoring of jobs both in the Research and Operations Departments, and provides common tools for scientists, analysts, and operators to cooperate. A large number of organisations organizations also use SMS (from both Member and non-Member States). Development and support of SMS has now stopped.
The replacement, ecFlow 4, has superseded SMS. It has been used for over a decade. It is a complete rewrite using an object-oriented methodology and modern standardised standardized components; it acts as a comprehensive replacement for SMS. The rewrite helps improve maintainability, allows easier modification, and introduces object orientated features. The proprietary script language used by SMS, CDP, have has been replaced by Python.
Development The development of ecflow 4 has now stopped. But support is still provided. It has been replaced by ecflow 5
You can find an introduction to ecFlow in the ECMWF Newsletter article (Autumn 2011), starting at on page 30.