Footnotes
Preface
1. The standard AS5506A was originally published in November 2004. The book covers its revision published in January 2009, as well as errata corrections approved in 2012. For more information on the AADL, go to the Web site www.aadl.info. To purchase a copy of the standard, go to the Web site www.sae.org/technical/standards/AS5506A.
2. Additional annexes are in development for ballot in late 2012: a revision of the Error Model Annex standard, a Requirements Definition and Analysis Annex, and a Code Generation Annex.
3. Details of the PBA system are provided in Appendix A.
Chapter 2
1. Listing A-1 in Appendix A summarizes the AADL syntax and grammar rules.
2. The Open Source AADL Tool Environment (OSATE) can be downloaded from www.aadl.info or the public AADL Wiki https://wiki.sei.cmu.edu/aadl.
3. There may be subtle differences in the implementation of the graphical representations in various tools (e.g., the label of <data> on a connection rather than the name of the connection).
Chapter 3
1. The detailed graphical representation of the implementation Complete.PBA_speed_control is taken from the OSATE environment.
2. In the next section we will demonstrate the addition of operational modes.
3. Since it is not the first character in the name, the numeric 1 can be used within the processor subcomponent name RT_1GHz. However, an implementation name Real_Time.1_GHz is not legal, since the numeric is the first character in the implementation identifier.
4. The resource allocation and scheduling analysis OSATE plug-in combines a bin-packing algorithm with scheduling algorithms. The OSATE tool is available for download from www.aadl.info.
5. Some scheduling policies may require additional properties, such as explicit priority assignment. The scheduling tool in OSATE assumes all periodic tasks without shared logical resources; other scheduling tools, such as Cheddar, accommodate the full set of tasks in AADL including tasks with shared data components.
6. If an AADL model has a single type of processor (i.e., only one processor speed) then the execution time is with respect to that processor. If there are multiple processors with different speeds, you can specify an execution time for each processor type (using in binding) or specify an execution time with respect to one of the other processors (the reference processor) using a scaling factor that is associated with each processor type. There is a Reference_Processor property and a Scaling_Factor property for this purpose.
7. These latency values are illustrative and do not reflect the performance of any particular device or speed control system.
8. Although we do not demonstrate this in the PBA example, the specific data types and data implementations can be added when the runtime categories are defined or even later in the process.
9. We could have developed an abstract implementation for the pilot interface component interface_pilot that included subcomponents and a complex internal structure. In that case, we would refine it to a system or other runtime category.
10. In some cases, you may use abstract components that you decide should become processes, leaving them incomplete and detailing their implementation later (e.g., by adding subcomponents).
Chapter 4
1. For more information on analysis, see AADL publications and presentations at www.aadl.info and the tool section of the public AADL Wiki at https://wiki.sei.cmu.edu/aadl.
2. Dispatch is used here to mean the initiation of execution.
3. Details of the PBA system are provided in Appendix A.
Chapter 5
1. Legal AADL identifiers are described in Section 12.1 and AADL reserved words are listed in Appendix A.4.
2. The component type identifier in a component implementation declaration must refer to a type declared in the same package or aliased from another package (see Section 12.2.3).
Chapter 10
1. Timing of connection communication is discussed in Section 10.1.5.
2. Although these omissions are permitted, within the OSATE environment a warning message will be generated to ensure that a user is aware of this situation.
3. We are assuming that there is a single periodic thread within the process input that sends data through the data port error_data and receives data through the data port error_response.
4. If the deadline and the dispatch are at the same time the transfer may be initiated just before the deadline to accommodate for the transfer overhead.
Chapter 15
1. See the AADL Tools section of the AADL Public Wiki (https://wiki.sei.cmu.edu/aadl) for publicly available tools, including those mentioned in this section.