SOFTWARE DESIGN METHODS AND REPRESENTATIONS - Software Design for Six-Sigma: A Roadmap for Excellence - page 90

Specification and Modeling

Task Assignment

Cost estimation

Allocation
Hardware/Software
Partitioning Scheduling

HW parts Interface parts SW parts

Communication
Synthesis

Specification
refinement

HW parts SW parts

HW
Synthesis

SW
Synthesis

Integration &
Implementation

FIGURE 4.1 Flow of a typical codesign system.

codesign systems normally impose restrictions on target architectures. For ex-
ample, allocation may be limited to a certain predefined components (Edwards
et al., 1997).
Hardware/software partitioning : This step partitions the specification into two
parts: 1) a part that will be implemented in hardware and 2) a part that will be
implemented in software.
Scheduling: This step is concerned with scheduling the tasks assigned to proces-
sors. If tasks information (i.e., execution time, deadline, and delay) are known,
scheduling is done statically at design time. Otherwise, scheduling is done dy-
namically at run time (i.e., using Real Time OS—RTOS). De Michell et al.
(Michell & Gupta, 1997) provide an overview of techniques and algorithms to
address the scheduling problem.