FIRST Scheduling Framework

Implementation under MaRTE OS

1. Introduction

The FIRST Scheduling Framework (FSF) is a real-time scheduling strategy based on the specification of service contracts between the application and the underlying operating system. Its main objectives are:

To be able to compose different applications, each one with its own scheduler.
To be able to analyse an application/component/subsystem independently from the rest of the system.
To add robustness by providing protection from timing faults in a subsystem.
To be able to support and analyse diverse timing requirements.
To be able to support explicitly adaptive applications.
To be able to do the above things on distributed systems.

The FSF service contract is extremely simple and powerful. It lets the application specify its minimum timing requirements, and also the way in which it can take advantage of additional spare processing capacity, if it is available. The FSF implementation guarantees the minimum requirements, and distributes the spare unused capacity among the different service contracts according to the application-specified quality and importance values.

FIRST is the acronym of the Flexible Integrating Scheduling Technology project, funded by the INFORMATION SOCIETY TECHNOLOGIES (IST) PROGRAM of the European Union. The participants are:

Mälardalen University, SWEDEN

University of York, UK

Universidad de Cantabria, SPAIN

Scuola Superiore S.Anna, ITALY

2. Documentation

A description of the architectural aspects of FSF can be found here.

FSF is not only an abstract description of a scheduling service, but is also implemented and available for trial use. It has an Application Program Interface that is independent of the underlying implementation. A description of the FSF API can be found in the Final Interface Definition and the details of its implementation in MaRTE OS are in FSF implementation documentation. The contents and a complete presentation of the C code of the FSF API are here

The usage and specification of the Ada version of the FSF API can be found in the FSF Ada version introductory documentation. The Makefile file allows for the generation of Ada or C programs. For any Ada program in the ada folder just type 'make <example>', being "<example>.adb" the file that contains the program to be generated. C programs in the test folder ar compiled in the same way, considerig the "<example>.c" the file that contains the program to be generated.

The current document is the home page for the FSF implementation under the MaRTE OS real-time operating system. An implementation is also available for the SHARK real-time operating system.

3. Download

The MaRTE OS implementation of FSF can be downloaded in two flavours:

The distributed one includes support for distributed systems using a specific version of the RT-EP protocol, and it may be downloaded with the complete setup for testing, which includes the necessary MaRTE OS distribution files, the GNAT 3.15 conpiler, the RT-GLADE support for tha Ada95 distributed Annex and the FSF itself already installed and ready to be used as a linux user folder in a large compressed tar file.

The single-processor one does not include support for distributed services inside the FSF API and may be downloaded from here. You will need a special version of MaRTE OS which contains some fixes and particular additions; this version may be downloaded from here. The complete MaRTE OS documentation can be found in the official MaRTE OS web page. The GNAT compiler necessary for MaRTEOS and used in this version is this.

4. Support

If you need any assistance with the current implementation of FSF on MaRTE OS please send an e-mail to Julio Medina: medinajl@unican.es