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dev/DEVELOPMENT.md

@@ -11,7 +11,7 @@ Knowledge of the [WRENCH C++ API](https://wrench-project.org/wrench/latest/api_d
 ![image](./overall_architecture.svg) 
 
 
-A Python simulator written using the WRENCH Python (left-hand side of the figure above) The Python API provides users with classes for simulation objects (`Task`, `File`, `BareMetalComputeService`, `StandardJob`, etc.), just like the [WRENCH C++ API](https://wrench-project.org/wrench/latest/api_developer.html) does. These objects are very thin and hold almost no state, and in particular no simulation state. All simulation state is held in the running WRENCH daemon (right-hand side of the figure). These thin Python objects provide some methods, and all these methods invoke a method of the `Simulation` class (which has some methods that can also be invoked directory).  This class answers these methods calls by placing REST API calls over HTTP sent to the WRENCH daemon.  These calls consists of a *path* (or route), which includes some static and some dynamic data, and of attached JSON dynamic data. 
+A Python simulator is written using the WRENCH Python (left-hand side of the figure above). The Python API provides users with classes for simulation objects (`Task`, `File`, `BareMetalComputeService`, `StandardJob`, etc.), just like the [WRENCH C++ API](https://wrench-project.org/wrench/latest/api_developer.html) does. These objects are very thin and hold almost no state, and in particular no simulation state. All simulation state is held in the running WRENCH daemon (right-hand side of the figure). These thin Python objects provide some methods, and all these methods invoke a method of the `Simulation` class (which has some methods that can also be invoked directory).  This class answers these methods calls by placing REST API calls over HTTP sent to the WRENCH daemon.  These calls consists of a *path* (or route), which includes some static and some dynamic data, and of attached JSON dynamic data. 
 
 The WRENCH daemon, implemented in C++, consists of two threads. The first is the HTTP server thread, which received REST API calls over HTTP. It defines all available routes and the specification of all expected data in the requests and all expected data in the responses. For each route, in invokes a particular method. Each of these methods takes in JSON data and returns JSON data.  The second is the simulation thread. This threads is a WRENCH simulator that is in charge of running the simulation based on incoming REST API requests. **Only this thread can issue simulated operations** (a bit of a difficult concept, ask lead developers :)).  So when the HTTP server thread receives a request to read simulation state, it can answer it directly. But when it receives a request that would modify simulation state, it cannot answer it and instead needs to communicate with the simulation thread.  This communication is via a thread-safe "work queue" data structure. The HTTP server threads puts "please do this" work units in the work queue, and the simulation thread retrieves these work units, does them, and replies to the HTTP server thread that it's been done.  Note that the requests coming over HTTP are all in text. That is, simulation objects are referred to by their names.  The WRENCH C++ API makes it possible to retrieve some simulation objects by their names, but not all.  The WRENCH daemon just has several helper "registry" data structures to keep track of some simulation objects by their names. 
 
@@ -37,7 +37,7 @@ The simplest way to learn how to do this is to go through a complete example. Le
 
 In the C++ API, a workflow is created by calling the static method `createWorkflow()` of the
 Workflow class. In the REST API, we thus need some path that can be
-requests to cause the creation of a workflow. You will note in
+requested to cause the creation of a workflow. You will note in
 `wrench/tools/wrench/wrench-daemon/doc/wrench-openapi.json` that all path
 have about the same prefix: `/simulation/{simid}/...`. Each running simulation
 has an ID, and all paths begin by specifying this ID. In that file, there is a path specified as: