Commit 9a724313 authored by Sven Gestegård Robertz's avatar Sven Gestegård Robertz
Browse files

started elaborating

parent 5f5757fe
......@@ -28,7 +28,10 @@ application sees fit.
The LabComm system is based on a binary protocol and
and a compiler that generates encoder/decoder routines for popular languages
including C, Java, and Python.
including C, Java, and Python. There is also a standard library for the
languages supported by the compiler, containing generic routines for
encoding and decoding types and samples, and interaction with
application code.
The LabComm compiler accepts type and sample declarations in a small language
that is similar to C or Java type-declarations.
......@@ -44,10 +47,15 @@ where the overhead of communication has to be kept at a minimum, hence LabComm
only requires one-way communication to operate. The one-way operation also has
the added benefit of making LabComm suitable as a storage format.
Two-way comminication adds complexity, in particular for hand-shaking
during establishment of connections, and the LabComm library provides
support for (for instance) avoiding deadlocks during such hand-shaking.
\section{Communication model}
LabComm provides self-describing communication channels, by always transmitting
a machine readable description of the data before actual data is sent.
a machine readable description of the data before actual data is
sent\footnote{Sometimes referred to as \emph{in-band} self-describing}.
Therefore, communication on a LabComm channel has two phases
\begin{enumerate}
......@@ -88,11 +96,34 @@ The roles in setting up, and maintaining, the configuration of a channel are as
\item if an unhandled signature is received, pauses the channel and informs the application
\end{itemize}
\subsection{Reconfiguration}
The fundamental communication model can be generalized to the life-cycle
of a concrete communication channel, including the transport layer,
between two end-points. Then, the communication phases are
\begin{enumerate}
\item \emph{Establishment} of communication channel at the transport layer
\item \emph{Configuration} of the LabComm channel (registration of sample
types)
\item \emph{Operation} (transmission of samples)
\end{enumerate}
where it is possible to \emph{reconfigure} a channel by transitioning
back from phase 3 to phase 2. That allows dynamic behaviour, as a sample
type can be added or redefined at run-time. It also facilitates error
handling in two-way channels.
\section{The Labcomm language}
The following examples do not cover the entire language
specification (see appendix~\ref{language_grammar}), but might serve as a
gentle introduction to the LabComm language.
The LabComm language is used to describe data types, and from such data
descriptions, the compiler generates code for encoding and decoding
samples. The language is quite similar to C struct declarations, with
some exceptions. We will now introduce the language through a set of
examples.
These examples do not cover the entire language
specification (see appendix~\ref{language_grammar} for the complete
grammar), but serve as a gentle introduction to the LabComm
language covering most common use-cases.
\subsection{Primitive types}
......
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