Abstract - Ph D thesis Thomas Gustafsson
Management of Real-Time Data Consistency and Workload Overloads
in Embedded Systems
This thesis addresses the issues of data management in embedded
systems' software. The complexity of developing and maintaining
software has increased over the years due to increased availability of
resources, e.g., more powerful CPUs and larger memories, as more
functionality can be accommodated using these resources.
In this thesis, it is proposed that part of the increasing
complexity can be addressed by using a real-time database since data
management is one constituent of software in embedded systems. This
thesis investigates which functionality a real-time database should
have in order to be suitable for embedded software that control an
external environment. We use an engine control software as a case
study of an embedded system.
The findings are that a real-time database should have support for
keeping data items up-to-date, providing snapshots of values, i.e., the
values are derived from the same system state, and overload handling.
Algorithms are developed for each one of these functionalities and
implemented in a real-time database for embedded systems. Performance
evaluations are conducted using the database implementation. The
evaluations show that the real-time performance is improved by
utilizing the added functionality.
Moreover, two algorithms for examining whether the system may
become overloaded are also outlined; one algorithm for off-line use and
the second algorithm for on-line use. Evaluations show the algorithms
are accurate and fast and can be used for embedded systems.