Data type definitions

When the ASSERT process reaches the system modeling stage, the overall system design must reference the data definitions that are exchanged between AP-Level containers. These definitions must include references to ASN.1 grammars, as shown in this extract from an actual AADL Dataview:

Figure 2.1: From ASN.1 to AADL/UML

PACKAGE DataTypes

PUBLIC

DATA POS
PROPERTIES
  -- name of the ASN.1 source file:
  Source_Text => ("PosData.asn1");
  -- Size of a buffer to cover ASN.1 representation:
  -- Real message size is 20; suggested aligned message buffer is...
  Source_Data_Size => 24 B;
  -- name of the corresponding data type in the ASN.1 file:
  Type_Source_Name => "TCLink";
END POS;

END DataTypes;

...and this one, from a UML Dataview:

<?xml version="1.0" encoding="UTF-8"?>
<rcm:Model xmi:version="2.0" xmlns:xmi="http://www.omg.org/XMI" 
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
    xmlns:rcm="http://rcm" name="DataTypes" >
  <rootPackage>
    <ownedMember xsi:type="rcm:DataType" name="T_POS" 
        Source_Text="PosData.asn1" Source_Data_Size="32" 
        Type_Source_Name="TCLink" />

The information kept per type includes the specific ASN.1 type (in this extract, TCLink) as well as the specific ASN.1 grammar file (``PosData.asn1''). Also included is "glue" specific information (e.g. the size of the message representation in the selected ASN.1 encoding).

These files are of course impossible to write manually, so appropriate tools have been built to that purpose: asn2aadlPlus and asn2uml.