MathWorks has a formal verification tool called Polyspace Code Prover. MathWorks' website claims that Polyspace uses formal mathematics to verify properties of programs. There is a free trial, but it isn't available to home users. Does anyone know if Polyspace has or uses a library of mathematical theories to formally verify properties of programs? If yes, in which language is this library written?
Polyspace's libraries are all internal and automated, and using them requires you to run your code analysis with Polyspace from its user interface, or command-line interface.
As evidenced by the page for the MathWorks' DO-178 Qualification Kit, Polyspace is a Formal Methods tool and can be qualified under DO-333 (the Formal Methods supplement). There is a similar capability for the MathWorks' IEC Certification Kit.
Related
I am currently developing a method for symbolically executing and testing IEC 61131-3 applications.
For evaluating my approach, I require non-trivial programs written in any of the languages defined in the standard.
Are there any openly accessible code bases I could use for this?
The OSCAT libraries is the biggest open code base written in IEC61131-3 afaik. They provide different libraries for different use cases and for different plc vendors
Furthermore there are some example programs available on Beckhoff Infosys. For almost every library they provide a sample section. One of the biggest samples is the OOP extension sample (OOP extensions are included in the new version of IEC61131-3, not sure if you are interested in it).
Another source of examples is the Codesys Store. They have some free and some paid examples.
And one more I like (but its only in german). M. Seitz the author of a good plc programming book provides some accompanying samples, one of them a bit bigger (coffee machine). There is also a simulation and control library available.
A very good source for examples is Beckhoff's information system which is also available for download.
You can find good examples of different methods for example under different libraries.
Some links:
Programming Reference (Good source)
OOP Sample
Standard library (Library containing IEC standard functions)
We'd like to offer a compiled library that implement a protocol layer to be imported into C/C++ source code project for microcontrollers. And eventually expose a sort of compiled function to the source code project. let's say a sort of "dll". Is there any know technique to realize something of similar?
While it is possible to provide functions via a library, generally in the microcontroller/embedded realm it quickly becomes impractical.
Each microcontroller core will have a unique instruction set. Further, micros from the same family may have a variety of extensions which are either supported or not... So you're left with providing a library file for each individual microcontroller (from each vendor) that you'd like to support.
But...
In my experience, calling conventions between compilers are not the same. So a library compiled by one toolchain will not be able to be linked to object files created by another toolchain.
That leads you to then provide a library for each individual micro from each vendor for each toolchain someone might use. Ick. Oh, and don't rely on an OS calls either, as you don't know what you'll be linked with...
A more conventional approach is to use the same approach RTOS vendors tend to use: provide the source, and protect your IP with licensing terms. The reality is that if your end users want to, they can step through the assembly and figure out exactly what is happening, so you're not hiding your implementation that carefully anyway.
Can you suggest on this points related to Autosar, taking into consideration I am a software developer who can write some software in C?
Now I Develop a functionality in C, that has to read some ECU specific data, process it & update some ECU specific data (which can be some variable or i/o signal).
Now how I will be using Autosar RTE & virtual functional bus?
What will be there use to a software developer?
Also, as Autosar says "standardization of interfaces" what does it mean? Does it mean that if some else anywhere around the world is also developing same functionality (in C language, like me) we both will be using same name of the API's for those I/O signals?
How RTE will be helpful for me in Unit testing? Or what really RTE is doing from software developer point of view?
http://www.autosar.org/gfx/AUTOSAR_TechnicalOverview_b.jpg
I read a lot technical terms... but being a software developer these points are important for me to know. Can you explain it a bit to me.
Your reply will be appreciated.
I don't think it is going to be that easy...
I believe that you are developing Autosar SWC (software component).
I would recommend for you to develop a portable C module. That has very clear inputs, outputs and req. on execution (check Autosar runnables).
Remember Autosar ECU includes RTOS, therefore your module will be part of a OS task.
When and if you come to the point of building an Autosar ECU, you will be able to wrap the module and connect ins/outs with Autosar virtual functional bus signals. For that you will need Autosar framework and probably configuration tools. These are complex and expensive.
Unit test the module the usual way you test C module.
Good luck.
P.S. RTE is just the "glue" code generated automatically by configuration tools according the configuration of ECU BSW and System Extract for that ECU. You will worry about it during wrapping.
The Idea behind dividing the functionality in AUTOSAR SWC and Basic software is to make the application SW development independent of any platform. To answer your questions.
RTE is giving the application a signal based interface, hence you expect the other SW components (inter-ECU /intra-ECU) to provide the required data in the form of signals, you dont care about the platform or type of communication medium
Yes by standardizing the interfaces (all kind of interactions), a software component or any Basic software module can be Fixed into the SW architecture. Read more about the different type of AUTOSAR interfaces.
Refer to answer 1
RTE is there as a layer to 'abstract' the inner components of the system. For example, if you need to get access to the system's installed flash memory, you have to use the RTE-related memory functions.
You are correct. You only need to read the specifications and use the corresponding functions to get your desired result in an AUTOSAR system.
RTE makes sure that the developers of the software components and the middle-layer systems would work properly with minimal interaction between them. SWC developers just need to read the AUTOSAR standard and follow it to ensure compatibility with the middle-layer systems, since it is expected that the middle-layer system developers would follow that same standard in providing functionalities on their side. It also helps developers with the portability of their software.
I think all your questions can be answered by reading the AUTOSAR standard documents at the AUTOSAR website. Most of my limited knowledge in development of AUTOSAR systems (started reading about it for close to a month already), I got there.
I am a Software developer who Developed a Console Application Tool for Autosar RTE, Test Case Generation for RTE, and wrote Unit Testing Scripts for the tool I created.
I Developed these using C# and NUnit Framework. Same can be Developed using C or a java or any other language. Ultimate goal is to generate AUTOSAR modules (.c and .h files) based on the requirement.
1. Software Developer Scope
As a Software Developer, i had a task to implement complete RTE and Test Applications for the Implemented RTE code.
Inputs and Outputs:
Basically our inputs were Software Component files and ECU Extract which were in ARXML format and Outputs were Rte and test application source and header files (.c and .h) which were created based on the requirements.
Tasks as a developer:
Here, as a developer, we need to perform Input parsing from AXXML to our own data structure, Schema Validation, Modal Validation, File generation etc.
2. Standardization
Yes, AUTOSAR Architecture provides standardized interface. Irrespective of the implementation strategy, API structure remains same which eases the usage. This acts as a generalised library where you can use already developed Module or you can implement the module in your own way by considering API specification. All you need is to follow the specifications provided for every module you use.
Requirement varies from Company to Company but the way of using APIs remains same.
3. Unit Testing
Unit Testing has nothing to do with RTE or AUTOSAR modules. You will be testing the Uints of Your Code. When i say your code, it is the one which you used to develop any particular module (eg. Rte.c) and not testing the generated module itself. You will be testing the Source code you developed to generate the specfic module. Your source code is not part of RTE or any other module implementation but is tool which generates the module implementation.
Overview:
Software developer have various scope in generating AUTOSAR modules depends on the Requirement.
You can develop a tool which will generate AUTOSAR modules.
You can develop an Editor which will is used to edit/create AUTOSAR XML files. (Eg: Artop)
Developing might sound complex as we do not get direct resources other than specifications. Once you are in, you will learn a lot.
To answer your question
If you will go through the Layered Architecture of AUTOSAR, you will come to know this architecture is followed to minimize the dependency of the each module
(layer) with lower layer.
Again, RTE is a like wrapper to separate the lower layered dependency, this enables to work on each layer independently. Most of the virtual buses are mapped with RTE, in my experience I have worked on IOC which is allowed to map with RTE and which communicates with other SWC's with memory and core boudary. To OS Developer its via to the application layer and Mapped software partitions.
The standard is used to maintain uniformation in all software layers, however to meet the requirements the developers may have different way of implementation and design, but the API's and requirements will be universal.
This is useful for standardised intefacing too.
For Unit testing of the developers OS design and implementation RTE works as abstract module.
Reading Specs for different module will resolve most of doubts.
I have trouble understanding XPCOM. How is it different from COM? What makes it cross platform?
Is it a framework with a set of libraries that you can use to do some jobs?
Also, does Component Object Model means every functionality is implemented in component so we can use it without knowing the detail implementation?
Can you someone help me understand this please?
Thanks,
Chan.
I have trouble understanding XPCOM.
How is it different from COM?
XPCOM is Mozilla's own, cross-platform (hence the XP bit) version of COM.
What makes it cross platform?
It is implemented in a library that has been ported to many platforms by contributors to the Mozilla open-source project. You can build it or download a binary for any platform that you wish and, in the extremely remote possibility that you want to use it on a platform that is not already supported, it should be straightforward to port it yourself.
Also, does Component Object Model
means every functionality is
implemented in component so we can use
it without knowing the detail
implementation?
Yes, spot on. The idea is for a language-independent framework that enables different components to communicate and interact, without requiring any special knowledge of the language that any particular component is implemented in. So javascript code can call C++ code, for instance.
This is achieved by components publishing well-defined interfaces, using a language called IDL (or, in XPCOM's case, XPIDL). These interfaces make use of well-defined types with mappings in each of the supporting languages. Every interface inherits from a common base interface, which provides standard methods for reference-counting and type-inference (called IUnknown in COM and nsISupports in XPCOM).
Can you someone help me understand
this please?
In terms of online resources, there are dedicated areas on both the MSDN (for COM) and the MDC (for XPCOM). If you want to really understand the motivation for COM and why it is the way it is, I recommend picking up Don Box's Essential COM. And of course, if you have any specific questions that need answering, you can always come here to ask them. :)
Whenever I ask people about the difference between an API and a library, I get different opinions. Some give this kind of definition, saying that an API is a spec and a library is an implementation...
Some will tell you this type of definition, that an API is a bunch of mapped out functions, and a Library is just the distribution in compiled form.
All this makes me wonder, in a world of web code, frameworks and open-source, is there really a practical difference anymore? Could a library like jQuery or cURL crossover into the definition of an API?
Also, do frameworks cross over into this category at all? Is there part of Rails or Zend that could be more "API-like," or "libraryesque"?
Really looking forward to some enlightening thoughts :)
My view is that when I speak of an API, it means only the parts that are exposed to the programmer. If I speak of a 'library' then I also mean everything that is working "under the hood", though part of the library nevertheless.
A library contains re-usable chunks of code (a software program).
These re-usable codes of library is linked to your program through APIs
(Application Programming Interfaces). That is, this API is an interface to library through which re-usable codes are linked to your application program.
In simple term it can be said that an API is an interface between two software programs which facilitates the interaction between them.
For example, in procedural languages like C, the library math.c contains the implementations of mathematical function, such as sqrt, exp, log etc. It contains the definition of all these functions.
These function can be referenced by using the API math.h which describes and prescribes the expected behavior.
That being said, an API is a specification (math.h explains about all the functions it provides, their arguments and data they return etc.) and a library is an implementation (math.c contains all the definitions of these functions).
API is part of library that defines how it will interact with external code. Every library has API, API is sum of all public/exported stuff. Nowadays meaning of API is widened. we might call the way web site/service interact with code as API also. You can also tell that some device has API - the set of commands you can call.
Sometimes this terms can be mixed together. For example you have some server app (like TFS for example). It has API with it, and this API is implemented as a library. But this library is just a middle layer between you and not the one who executes your calls. But if library itself contains all action code then we can't say that this library is API.
I think that Library is a set of all classes and functions that can be used from our code to do our task easily. But the library can contain some of its private functions for its usage which it does not want to expose.
API is a part of library which is exposed to the user. So whatever documentation we have regarding a library, we call it an API Documentation because it contains only those classes and functions to which we have access.
we have first to define an interface ...
Interface :is the means by which 2 "things" talk to each other and exchange information. "things" could be a (1) human or (2) a running code of any sort (e.g. library ,desktop application , OS , web service ... etc).
if a human want to talks to a program he need Graphical user interface (GUI) or command line interface (CLI). both are types of interfaces that humans (but not programs) would like to use.
if however a running code (of any sort) want to talk to another running code (of any sort) it doesn't need or want a GUI or CLI ,it rather need an Application Programming Interface (API).
so to answer the original poster question : library is a type of running code and the API is the means by which this running code talk to other running codes.
In Clear and concise language
Library: Collection of all classes and methods stored for re-usability
API: Part of library classes and methods which can be used by a user in his/her code.
According to my perspective, whatever the functions are accessible to invoker , we can called as api in library file, library file having some of the functions which is private , we cannot access them ..
There are two cases when we speak or think of API
Computer program using library
Everything else (wider meaning)
I think, that in the first case, thinking in terms of API is confusing. It's because we always use a library. There are only libraries. API without library doesn't exist, while there's a tendency to think in such terms.
How about The Standard Template Library (STL) in C++? It's a software library.
You can have different libraries with the same API, meaning set of available classes, objects, methods, functions, procedures or whatever terms you like in some programming language. But it can be said, that we have different implementation of some "standard" library.
Some analogy may be that: SQL is a standard but can have different implementations. What you use is always some SQL engine which implements SQL. You may follow only standard set of features or use some extended, specific to that implementation.
And what "under the hood" in library is not your concern, except in terms of differences in efficiency by different implementations of such library.
Of course I'm aware, that this way of thinking is not what is a "generally binding standard". Just a lot of new terms have been created, that are not always clear, precise, intuitive, that brings some confusion. When Oracle speaks about Collections. It's not library, it's not API, it's a "Collections Framework".
Hello brothers and sisters.
Without using technical terms I would like to share my understanding regarding API and library.
The way I distinguish 'library' and 'API' is imagining a situation where I go to a book library. When I go there, I request a book which I need to a 'librarian' without knowing how a entire library is managed.
I make a simple relation between them like this.
Library = A book library which has a whole system and staffs to manage books.
API = A librarian who provides me a simple access to a book which I need.