Design and Implementation of TinyGALS: A Programming Model for ...

Component interface for COUNTER.
COMPONENT COUNTER;
ACCEPTS{
char init(void);
void fire(void);
};
USES{
char fireOut(short value);
};
Figure 2: Fragment of code for interface definition of the COUNTER com-
ponent shown in Figure 1.
2.2.2 TinyGALS Modules
Modules are the major building blocks of a TinyGALS program, encompassing one or more
TinyGALS components. A TinyGALS module M is a 6-tuple:
M = (COMPONENT SM,INITM,INPORT SM,OUT PORT SM,PARAMET ERSM,LINKSM),
where COMPONENT SM is the set of components that form the module; INITM is a list
of initialization methods that belong to the components in COMPONENT SM; INPORT SM
and OUT PORT SM are sets that specify the input ports and output ports of the module, re-
spectively; PARAMET ERSM is a set of variables external to the components 5 ; and LINKSM
specifies the relations among the interface methods of the components (IC in Equation 1)
and the input and output ports of the module (INPORT SM and OUT PORT SM). Section
2.3.3 describes links in more detail, including which configurations of components within
a module are valid.
Modules are different from components; INPORT SM and OUT PORT SM of a module
M are not the same as ACCEPT SC and USESC of a component C. While ACCEPT SC
5 Refer to information on TinyGUYS in Section 2.4.
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