[aadl]: New release of Cheddar

[Pierre Dissaux]

Dear AADL user,

We are pleased to announce a new release of Cheddar.
Cheddar is a free real time scheduling tool. Cheddar is designed for
checking task temporal constraints and buffer sizes of a real time
application/system.
It can also help you for quick prototyping of real time schedulers.
Finally, it can be used for educational purposes.
Cheddar is developed and maintained by the LISyC Team,
University of Brest.
Since 2008, Ellidiss Technologies also contributes to the development of
Cheddar and provides industrial support.
Cheddar is written in Ada and runs on Linux and win32 boxes.

Thanks to R. Couillet, P. Dissaux, J. Hugues, N. Vienne, P. Wong (bugs 
fixed/reports)

The current release is now 2.1. If you are a regular Cheddar's user, we 
strongly advice you to switch
to the 2.1 release. See "ChangesLog.pdf" and "FIXED_BUGS.pdf" files for more 
information.

1) New features summary :
------------------------

* AADL translation when an AADL file is loaded in Cheddar command line.

* Update Ocarina from 1.0 to 1.1.

* New user-defined scheduler modeling feature : you can now model your 
scheduler
  entity synchronizations by a set of timed automata. See the ACM SIGAda Ada 
Letters
  article of 2007 for further details.

* Cheddar menu simplification.

* Compilation on Linux and Windows Box simplification.

* Many fixed bugs : important scheduling simulation memory leak fix, 
precedences graph, ...


2) General Cheddar features :
------------------------

Cheddar is composed of two independent parts : an editor used to
describe a real time application/system, and a framework.
The editor allows you to describe systems composed of several processors
which own tasks, shared resources, buffers and which exchange messages.
Such a systems specification can be expressed with AADL, the architecture
and design language from the SAE.
The framework includes many feasibility tests and simulation tools.
Feasibility tests
can be applied to check that task response times are met and that
buffers have bounded size.
When feasibility tests can not be applied, the studied application can
be analyzed with scheduling and buffer simulations.
Cheddar provides a way to quickly define "user-defined schedulers" to
model scheduling of ad-hoc applications/systems (ex : ARINC 653).
The most important analysis tools are the following :

- Do scheduling simulations with classical real time schedulers
         (Rate Monotonic, Deadline Monotonic,
         Least Laxity First, Earliest Deadline
         First, POSIX queueing policies : SCHED_OTHERS,
         SCHED_FIFO and SCHED_RR) with
         different type of tasks (aperiodic, periodic, task
         activated with a poisson process law, ...)
- Extract information from scheduling simulation.
         (buffer utilization factor, task response times, task missed
            deadlines,
         number of preemption, ...)
- Apply feasibility tests on tasks and buffers (without scheduling
         simulation) :
         - Compute task response time bounds.
         - Apply processor utilization tests.
         - Compute bound on buffer size (when buffers are shared by periodic 
tasks)
- Shared resources support (scheduling and
         blocking time analysis).  Supported protocols : PIP, PCP.
- Tools to express and do simulations/feasibility tests with task
         precedencies :
         - Schedule tasks according to task precedencies
         - Compute Tindell end to end response time.
         - Apply Chetto and Blazewicz algorithms.
- Tools to run scheduling simulation in the case of
         multiprocessors systems
- Do simulation when tasks are randomly activated.
- Can run scheduling simulation on user-defined scheduler
         and task arrival patterns.
- Run user-defined analysis on scheduling simulation.
- ...


Cheddar is distributed under the GNU GPL license.
It's a free software, and you are welcome to  redistribute it under
certain conditions;
See the GNU General Public License for  details.

Source code, binaries and documentations can be freely downloaded from
http://beru.univ-brest.fr/~singhoff/cheddar


Best Regards

Frank Singhoff (LISyC Team, University of Brest)
Alain Plantec (LISyC Team, University of Brest)
Jerome Legrand (Ellidiss Technologies)