+@subsection s4u_ex_activity_exec Executions (using the CPU)
+
+ - <b>Basic execution</b>.
+ @ref examples/s4u/exec-basic/s4u-exec-basic.cpp \n
+ The computations done in your program are not reported to the
+ simulated world, unless you explicitely request the simulator to pause
+ the actor until a given amount of flops gets computed on its simulated
+ host. Some executions can be given an higher priority so that they
+ get more resources.
+
+ - <b>Asynchronous execution</b>.
+ @ref examples/s4u/exec-async/s4u-exec-async.cpp \n
+ You can start asynchronous executions, just like you would fire
+ background threads.
+
+ - <b>Monitoring asynchronous executions</b>.
+ @ref examples/s4u/exec-monitor/s4u-exec-monitor.cpp \n
+ This example shows how to start an asynchronous execution, and
+ monitor its status.
+
+ - <b>Remote execution</b>.
+ @ref examples/s4u/exec-remote/s4u-exec-remote.cpp \n
+ Before its start, you can change the host on which a given execution will occur.
+
+ TODO: add an example about parallel executions.
+
+@subsection s4u_ex_activity_io I/O (using disks and files)
+
+SimGrid provides two levels of abstraction to interact with the
+simulated storages. At the simplest level, you simply create read and
+write actions on the storage resources.
+
+ - <b>Access to raw storage devices</b>.
+ @ref examples/s4u/io-storage-raw/s4u-io-storage-raw.cpp \n
+ This example illustrates how to simply read and write data on a
+ simulated storage resource.
+
+The FileSystem plugin provides a more detailed view, with the
+classical operations over files: open, move, unlink, and of course
+read and write. The file and disk sizes are also dealt with and can
+result in short reads and short write, as in reality.
+
+ - <b>File Management</b>. @ref examples/s4u/io-file-system/s4u-io-file-system.cpp \n
+ This example illustrates the use of operations on files
+ (read, write, seek, tell, unlink, ...).
+
+ - <b>Remote I/O</b>.
+ @ref examples/s4u/io-file-remote/s4u-io-file-remote.cpp \n
+ I/O operations on files can also be done in a remote fashion,
+ i.e. when the accessed disk is not mounted on the caller's host.
+