-\section{Conclusion}
-
\section{Discussion}
+\todo{class based shallow doesn't have multiple backend support}
+\todo{slow client software because of interpretation}
+\todo{What happens if a device dies? Task resending, add to handshake}
\section{Future Research}
+The system is still crude and a proof of concept. Improvements and extension
+for the system are amply available in several fields of study.
+
+\subsection{Simulation}
+An additional simulation view to the \gls{mTask}-\gls{EDSL} could be added that
+works in the same way as the existing \gls{C}-backed simulation. It simulates
+the bytecode interpretation. Moreover would be possible to let the simulator
+function as a real device, thus handling all communication through the
+existing \gls{SDS}-based systems and behave like a real device. At the moment
+the \emph{POSIX}-client is the reference client and contains debugging code.
+Adding a simulation view to the system allows for easy interactive debugging.
+However, it might not be easy to devise a simulation tool that accurately
+simulates the \gls{mTask} system accurately on some levels. The semantics can
+be simulated but timing and peripheral input/output are more
+difficult to simulate properly.
+
+\subsection{Optimization}
+True multitasking could be added to the client software. This allows
+\gls{mTask}-\glspl{Task} to run truly parallel. All \glspl{mTask} get slices
+of execution time and will each have their own interpreter state instead of one
+system-wide one that is reset after am \gls{mTask} finishes. This does require
+separate stacks for each \gls{Task} and therefore increases the system
+requirements of the client software. However, it could be implemented as a
+compile-time option and exchanged during the handshake so that the server knows
+the multithreading capabilities of the client.
+
+Hardly any work has been done in the interpreter. The current interpreter is a
+no nonsense stack machine. A lot of improvements can be done in this part. For
+example, precomputed \emph{gotos} can improve jumping to the correct part of
+the code corresponding to the correct instruction.
+
+\subsection{Resources}
+Resource analysis during compilation can be useful to determine if an
+\gls{mTask}-\gls{Task} is suitable for a specific device. If the device does
+not contain the correct peripherals such as an \gls{LCD} then the
+\gls{mTask}-\gls{Task} should be rejected and feedback to the user must be
+given.
+
+This idea could be extended to the analysis of stack size and possibly
+communication bandwidth. With this functionality ever more reliable fail-over
+systems can be designed. When the system knows precise bounds it can
+allocate more \glspl{Task} on a device whilst staying within safe memory
+bounds. The resource allocation can be done at runtime within the backend
+itself or a general backend can be devices that can calculate the resources
+needed for a given \gls{mTask}. A specific \gls{mTask} cannot have multiple
+views at the same time due to the restrictions of class based shallow
+embedding. It might even be possible to encode the resource allocation in the
+type system itself using forms of dependant types.
+
+\subsection{Functionality}
+More \gls{Task}-combinators already existing in the \gls{iTasks}-system could
+be added to the \gls{mTask}-system to allow for more fine-grained control flow
+between \gls{mTask}-\glspl{Task}. In this way the new system follows the
+\gls{TOP} paradigm even more and makes programming \glspl{mTask} for
+\gls{TOP}-programmers more seamless. Some of the combinators require previously
+mentioned extension such as the parallel combinator. Others might be achieved
+using simple syntactic transformations.
+
+Currently the \gls{C}-view allows \glspl{Task} to launch other \glspl{Task}. In
+the current system this type of logic has to take place server side. Adding
+this functionality to the bytecode-view allows greater flexibility, easier
+programming and less communication resources. Adding these semantics requires
+modifications to the client software and extensions to the communication
+protocol since relations between \glspl{Task} also need to be encoded and
+communicated.
+\section{Conclusion}
+This thesis introduces a new view for the existing \gls{mTask}-\gls{EDSL}.
+The new view for the \gls{EDSL} compiles the language in to bytecode that can
+be interpreted by an \gls{mTask}-client. Clients have been written for several
+microcontrollers and consumer architectures that can be connected through
+various means of communication such as serial, bluetooth, wifi and wired
+network communication. The bytecode on the devices is interpreted using a
+simple stack machine and provides the programmer interfaces to the peripherals.
+The semantics of the \glspl{mTask} tries to resemble the \gls{iTasks} semantics
+as close as possible.
+
+The host language has a very efficient compiler and code generator. Therefore,
+the \gls{mTask}-system is also relatively fast because the compilation of
+\glspl{mTask} is nothing more than running some functions in the host language.
+
+The dynamic nature allows the microcontroller to be programmed once and used
+many times. The program memory of microcontrollers often guarantees around
+$10.000$ write or upload cycles and therefore existing techniques such as
+generating \gls{C} code are not usable for dynamic \gls{Task} environments.
+The dynamic nature also allows the programmer to design fail-over mechanisms.
+When a device is assigned a \gls{Task} but another device suddenly becomes
+unusable, the \gls{iTasks} system can reassign a new \gls{mTask}-\gls{Task} to
+the first device that possibly takes over some of the functionality of the
+broken device without needing to recompile the code.
repositories / msc-thesis1617.git / blobdiff