1.2 What is a Data Level?

The data level deals with the following aspects of information occurring inside a TCAD framework:

Representational Aspects
TCAD data has to be represented in a problem-specific way in formats and structures commonly understood by all tools and services inside the framework. Persistent and volatile representations of TCAD data on files and in memory with respective procedural interfaces to access these data have to be developed.

Logistical Aspects
The data level has to ensure that the correct type of data with correct contents is available in the correct representation at a specific time for a TCAD tool. Therefore the data level has to keep track of the data and data flow inside the framework, it has to ``know'' which kind of information is present where.

Communicational Aspects
Data has to be communicated amongst tools and between tools and the framework. This does not only relate to input and output data which the tool necessarily needs and produces, it also encompasses messages, error conditions, and signals to be transmitted properly in the framework.

Semantical Aspects
Similar data may be represented in many - often ambiguous ways - with a certain data representation. It is the data level's duty to resolve those ambiguities as far as possible, or preclude the occurrence of such ambiguities due to the design of its data representation syntaxes. The ambiguities which cannot be resolved by the data level have to be tackled by the task level, which specifically knows what global semantics a tool implies on the data that it needs and produces.