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 the
-\gls{mTask}-system is also relatively fast because the compilation of
+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
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
+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.
-
\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}
-Future improvements of the system could be:
-\begin{itemize}
- \item Add an additional simulation view to the \gls{mTask}-\gls{EDSL} that
- simulates the bytecode interpreter and possibly functions as a full
- fledged device, thus handling all communication through the existing
- system.
- \item Add true multitasking to the client software allowing
- \gls{mTask}-\glspl{Task} to run truly parallel. This does require
- separate stacks for each 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.
- \item 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 could also be extended to minimum stack size needed to
- run the task and memory requirements for storing the \gls{Task}.
- \item Implement more \gls{Task} combinators such as the step combinator to
- allow for more fine-grained control flow between
- \gls{mTask}-\glspl{Task}. This could be extended to a similar system
- as in the \gls{C}-code generation view. The \glspl{Task} can launch
- other \glspl{Task} and compose \glspl{Task} of subtasks.
-\end{itemize}
+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 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 for example 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 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.
+
+\todo{Parametric lenses on devices share?}
+
+\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 preciser 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} can not 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 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 tasks to launch other tasks. 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 tasks also need to be encoded and
+communicated.
repositories / msc-thesis1617.git / blobdiff