Reducing Ada code bases with adareducer
How we're using Libadalang to create an automated Ada code reducer.
101 entries tagged with #GitHub
How we're using Libadalang to create an automated Ada code reducer.
Ever wanted to understand why program proof is not as easy as telling ChatGPT "can you prove that program <code>stuff</code> is correct for me?" A new book from top-notch programmer and program proof expert Rustan Leino answers all your questions. Or at least a good batch.
The VSS (as an abbreviation for Virtual String Subsystem) library is designed to provide advanced string and text processing capabilities. It offers a convenient and robust API that allows developers to work with Unicode text, regardless of its internal representation. In this article, we will introduce you to the library and explain its purpose, highlighting its usefulness for developers working in this area.
From time to time we see, here and there, discussions in the Ada community about the design and adoption of a common logo to represent the language. Today we want to bring our contribution to this discussion by offering a logo to the Ada community.
A few months ago I was reading this article about coroutines in game development and how they are great tools for writing scripts (as in movie scripts) in the same language as the game engine. Until then I heard about coroutines but never really gave them a thought, this piqued my curiosity.
Every year since 2015, a team of dedicated individuals led by Eric Wastl organizes an online programming challenge called: Advent of Code. The concept is simple yet brilliant: from December 1st to 25th, every day a new small programming exercise is published on the adventofcode.com website. This year we want to join the fun, and bring a little bit of extra motivation for a good cause.
Writing secure software in C is hard. It takes just one missed edge case to lead to a serious security vulnerability, and finding such edge cases is difficult. This blog post discusses a recent vulnerability in a popular SHA-3 library and how the same problems were avoided in my own SHA-3 library written in SPARK.
While implementing application logic in Ada or SPARK is an improvement over a pure C project, its weakest link is still the C code in the SDK. On the other hand, there are many libraries, board support packages, and SDKs written in Rust, easily usable with Cargo. So instead of building the Ada application on top of a C base, one could use a Rust base instead to combine the large catalog of ready-to-use software with Rust's safety features, providing a much more solid base for an Ada project.
For years in this blog my colleagues and I have published examples, demos, and how-to’s on Ada/SPARK embedded (as in bare-metal) development. Most of the time, if not always, we focused on one way of doing things: to start from scratch and write everything in Ada/SPARK, from the low level drivers to the application. While this way of doing Ada/SPARK embedded will yield the best results in terms of software quality, it might not be the most efficient in all cases. In this blog post I want to present an alternative method to introduce Ada/SPARK into your embedded development projects.
We are pleased to announce the publication of the initial draft of the Ferrocene Language Specification (FLS) - a qualification-oriented document that details the Rust language as it specifically relates to Ferrocene.
We're happy to announce our the second edition of our programming competition, the Ada/SPARK Crate Of The Year Award! We believe the Alire package manager is a game changer for Ada/SPARK, so we want to use this competition to reward the people contributing to the ecosystem.
Today we have two exciting announcements for the future of the Ada/SPARK ecosystem.
A retrospective on learning Ada and developing a tool with it in 2021 from 2021 Ada Crate of the Year Winner Paul Jarrett.
A few weeks ago a piece of code went viral in the online dev community. The “Quite OK Image Format” (QOI) is a fast, lossless image compression designed to have a very simple implementation (about 300 lines of C). Shortly, a few alternative implementations popped up here and there, and in this kind of situation we are eager to show what Ada/SPARK can bring to the table.
Manuel Hatzl is the winner of the 2021 SPARK Crate of the year! In this blog post he shares his experience using Ada/SPARK and how he created the spark_unbound library
In June of 2021 we announced the launch of a new programming competition called Ada/SPARK Crate Of The Year Awards. We believe the Alire source package manager is a game changer for Ada/SPARK, so we want to use this competition to reward the people contributing to the ecosystem. Today we are pleased to announce the results. But first, we want to congratulate all the participants, and the Alire community at large, for reaching 200 crates in the ecosystem in January of this year. We truly believe in a bright future for the Ada/SPARK open-source ecosystem with Alire at the forefront. Reaching this milestone is a great sign, inside and outside the Ada/SPARK community, of the evolution and the energy of the ecosystem.
SPARKNaCl is a SPARK version of the TweetNaCl cryptographic library, developed by formal methods and security expert Rod Chapman. For two years now, Rod has been developing and optimizing this open-source cryptographic library while preserving the automatic type-safety proof across code changes and tool updates. He has recently given a talk about this experience that I highly recommend.
A few days ago, someone asked on the Ada Drivers Library repository how to add support for the SAMD21 micro-controller. Nowadays, I would rather recommend people to contribute this kind of micro-controller support project to the Alire ecosystem. I started to write a few instructions on how to get started, but it quickly became a blog-worthy piece of text.
This blog entry shows how to define an abstract data type that allows tasks to block on objects of the type, waiting for resumption signals from other components, for at most a specified amount of time per object. This "timeout" capability has been available in Ada from the beginning, via select statements containing timed entry calls. But what about developers working within the Ravenscar and Jorvik tasking subsets? Select statements and timed calls are not included within either profile. This new abstraction will provide some of the functionality of timed entry calls, with an implementation consistent with the Ravenscar and Jorvik subsets.
We're happy to announce our new programming competition, the Ada/SPARK Crate Of The Year Award! We believe the Alire package manager is a game changer for Ada/SPARK, so we want to use this competition to reward the people contributing to the ecosystem.
This post continues our adventures with SPARKNaCl - our verified SPARK version of the TweetNaCl cryptographic library. This time, we'll be looking at yet more performance improvement via proof-driven "operator narrowing", porting the library to GNAT Community 2021, and the effect that has on proof and performance of the code.
I am following the evolution of the embedded Rust community and in particular the work of James Munns from Ferrous-Systems. One of the projects that caught my attention is bbqueue, a single producer, single consumer, lockless, thread safe queue, based on BipBuffers.
This blog goes into the details of both measuring and improving the runtime performance of SPARKNaCl on a real "bare metal" embedded target, and comparing results with those for the original "TweetNaCl" C implementation.
Using GNAT Pro with containerization technologies, such as Docker, is so easy, a whale could do it!
In this blog post I want to present a new tool that allows one to very quickly and easily start Ada programming on any ARM Cortex-M or RISC-V microcontroller.
Some of you may recall an AdaCore blog post written in 2017 by Thales engineer Lionel Matias titled "Leveraging Ada Run-Time Checks with Fuzz Testing in AFL". This insightful post took us on a journey of discovery as Lionel demonstrated how Ada programs, compiled using GNAT Pro and an adapted assembler pass can be subjected to advanced fuzz testing. In order to achieve this Lionel demonstrated how instrumentation of the generated assembly code around jump and label instructions, could be subjected to grey-box (path aware) fuzz testing (using the original AFL v2.52b as the fuzz engine). Lionel explained how applying the comprehensive spectrum of Ada runtime checks, in conjunction with Ada's strong typing and contract based programming, enhanced the capabilities of fuzz testing beyond the abilities of other languages. Ada's advanced runtime checking, for exceptions like overflows, and the scrutiny of Ada's design by contract assertions allow corner case bugs to be found whilst also utilising fuzz testing to verify functional correctness.
Guillermo Perez's project won a finalist prize in the Make with Ada 2019/20 competition. This project was originally posted on Hackster.io here. For those interested in participating in the 2020/21 competition, registration is now open and project submissions will be accepted until Jan 31st 2021, register here.
A few years ago we realized that having a package manager for the Ada/SPARK community would be a game changer. Since then, AdaCore has been sponsoring and contributing to the Alire project created by Alejandro Mosteo from the Centro Universitario de la Defensa de Zaragoza. With this blog post I want to introduce Alire and explain why this project is important for the `Ada`/`SPARK` community.
Blaine Osepchuk's project won a finalist prize in the Make with Ada 2019/20 competition. This project was originally posted on Hackster.io here. For those interested in participating in the 2020/21 competition, registration is now open and project submissions will be accepted until Jan 31st 2021, register here.
Laurent Zhu's and Damien Grisonnet's project was accomplished for the EPITA Ada courses and won a finalist prize in the Make with Ada 2019/20 competition.
Starting today, AdaCore has put in place a Code of Conduct (CoC) to ensure a positive environment for everyone willing and wanting to interact with us. With the development of this blog, our twitter accounts, and our GitHub corporate account, there is more and more communication between AdaCore and a number of communities. In this Code of Conduct we want to explain how we are going to moderate the AdaCore-maintained community spaces with the goal of maintaining a welcoming, friendly environment.
A code obfuscator is a method of sharing coding discussions of real-world examples without giving away proprietary or classified information. This article shows an example of an Ada obfuscator, written in the SPARK language and using the Libadalang library to intelligently hide names and text within the source.
Hedley Rainnie's project combines 6 different SoCs all programmed in Ada performing as a LoRa network. He also showcases a BLE bridge to a LoRa server. His project came about when him and his wife were musing about how to detect and deter unwanted garden visitors. This ongoing project won a finalist prize in the 2019/20 Make with Ada competition.
Shahariar's project ensures safety against electrical fire or shock during an earthquake, flood, gas leakage or fire breakout by disconnecting the mains with a smart circuit breaker. Additionally, this project won a finalist prize in the 2019/20 Make with Ada competition.
John Singleton's The SmartBase makes your existing adjustable bed safer and easier to use by adding voice control and safe (and fun!) LED underbed lighting! Additionally, this project won first place prize in the 2019/20 Make with Ada competition.
Last year, I started evaluating programming languages for a formally-verified operating system. I've been developing software for a while, but only recently began work in high integrity software development and formal methods. There are several operating system projects, like the SeL4 microkernel and the Muen separation kernel, that make use of formal verification. But I was interested in using a formally-verified language to write a general-purpose OS - an environment for abstracting the underlying hardware while acting as an arbiter for running the normal applications we're used to.
This blog entry describes the transformation of an Ada stack ADT into a completely proven SPARK implementation that relies on static verification instead of run-time enforcement of the abstraction’s semantics. We will prove that there are no reads of unassigned variables, no array indexing errors, no range errors, no numeric overflow errors, no attempts to push onto a full stack, no attempts to pop from an empty stack, that subprogram bodies implement their functional requirements, and so on. As a result, we get a maximally robust implementation of a reusable stack abstraction providing all the facilities required for production use.
Not long ago, AdaCore published its LLVM frontend for GNAT. Also quite recently Espressif updated their LLVM backend to LLVM 9 which also happens to be the LLVM version of GNAT. This gave me to the idea to try out if LLVMs promise of providing modular and reusable toolchain technologies is true.
For an upcoming project, I needed a simple way of transferring binary files over an Ethernet connection with minimal (if any at all) user interaction. A protocol that's particularly appropriate for this kind of usage is the Trivial File Transfer Protocol (TFTP).
Over the last few months, I developed a SPARK version of the TweetNaCl cryptographic library. This was made public on GitHub in February 2020, under the 2-clause BSD licence. This blog entry goes into a bit more technical detail on one particular aspect of the project: the challenge of re-writing and verifying "constant time" algorithms using SPARK.
Having previously shown how to create a Web application in Ada, it's not so difficult to create an Android application in Ada. Perhaps the simplest way is to install Android Studio. Then just create a new project and choose "Empty Activity". Open the layout, delete TextView and put WebView instead.
As a demonstration for the use of Ada and SPARK in very small embedded targets, I created a remote-controlled (RC) car using Lego NXT Mindstorms motors and sensors but without using the Lego computer or Lego software. I used an ARM Cortex System-on-Chip board for the computer, and all the code -- the control program, the device drivers, everything -- is written in Ada. Over time, I’ve upgraded some of the code to be in SPARK. This blog post describes the hardware, the software, the SPARK upgrades, and the repositories that are used and created for this purpose.
Martyn’s recent blog post showed small programs based on Libadalang to find uses of access types in Ada sources. Albeit short, these programs need to take care of all the tedious logistics around processing Ada sources: find the files to work on, create a Libadalang analysis context, use it to read the source files, etc. Besides, they are not very convenient to run:
The GNAT-LLVM project provides an opportunity to port Ada to new platforms, one of which is WebAssembly. We conducted an experiment to evaluate the porting of Ada and the development of bindings to use Web API provided by the browser directly from Ada applications.
I was quite happy to see AdaFruit release their first Feather format board including a micro-controller with plenty of Ada support, the STM32F4. I bought a board right away and implemented some support code for it.
I’ve been telling Ada developers for a while now that Libadalang will open up the possibility of more-easily writing Ada source code analysis tools. (You can read more about Libadalang here and here and can also access the project on Github.)
Handling binary data is hard. Errors in parsers routinely lead to critical security vulnerabilities. In this post we show how the RecordFlux toolset eases the creation of formally verified binary parsers in SPARK.
How I learned to write SPARK-provable code using Conway's Game Of Life
Presenting the GNAT LLVM projectAt AdaCore labs, we have been working for some time now on combining the GNAT Ada front-end with a different code generator than GCC.
Interested in participating in the evolution of the Ada or SPARK languages? We have something for you.
In this blog post, I will present one of the most interesting additions to the community 2019 version of SPARK: pointer support. One of the core assumption in SPARK has always been the absence of aliasing, so adding pointers without breaking this assumption was quite a challenge. I will explain how this was achieved using an ownership model for pointers (like is done in Rust) through small examples.
C is the dominant language of the embedded world, almost to the point of exclusivity. Due to its age, and its goal of being a “portable assembler”, it deliberately lacks type-safety, opening up exploit vectors. Proposed solutions are partitioning the application into smaller intercommunicating blocks, designed with the principle of least privilege in mind; and rewriting the application in a type-safe language. We believe that both approaches are complementary and want to show you how to combine separation and isolation provided by MultiZone together with iteratively rewriting parts in Ada. We will take the MultiZone SDK demo and rewrite one of the zones in Ada.
The is the first part of a multiple part post that covers the development of the AdaFractal project. The idea was to create fractals in Ada. Here we will cover how to use AWS to create a flexible and portable way to display the generated fractals without using bulky graphics libraries.
When I bought the TinyFPGA-BX board, I thought it would be an opportunity to play a little bit with FPGA, learn some Verilog or VHDL. But when I discovered that it was possible to have a RISC-V CPU on it, I knew I had to run Ada code on it.
We are very proud to announce the availability of our new Ada and SPARK learning platform learn.adacore.com, which will replace AdaCoreU(niversity) e-learning platform. Learn all about it in this blog post.
ANSSI, the French national security agency, has published the results of their work since 2014 on designing and implementing an open-hardware & open-source USB key that provides defense-in-depth against vulnerabilities on the USB hardware, architecture, protocol and software stack. In this project called WooKey, Ada and SPARK are key components for the security of the platform. This is a very compelling demontration of both the usability and the power of safe languages and formal verification to develop secure systems.
Last week, the programmer Hillel posted a challenge (the link points to a partial postmortem of the provided solutions) on Twitter for someone to prove a correct implementation of three small programming problems: Leftpad, Unique, and Fulcrum.
PolyORB, AdaCore's versatile distribution middleware, now lives on Github. Its new home is https://github.com/AdaCore/polyorb
This is part #2 of the SPARKZumo series of blog posts. This post covers the build system that was used to build the SPARKZumo project and how to automate the process in GPS.
So you want to use SPARK for your next microcontroller project? Great choice! All you need is an Ada 2012 ready compiler and the SPARK tools. But what happens when an Ada 2012 compiler isn’t available for your architecture?
Updated July 2018
Tokeneer is a software for controlling physical access to a secure enclave by means of a fingerprint sensor. This software was created by Altran (Praxis at the time) in 2003 using the previous generation of SPARK language and tools, as part of a project commissioned by the NSA to investigate the rigorous development of critical software using formal methods. The project artefacts, including the source code, were released as open source in 2008. Tokeneer was widely recognized as a milestone in industrial formal verification. We recently transitioned this software to SPARK 2014, and it allowed us to go beyond what was possible with the previous SPARK technology. We have also shown how security vulnerabilities introduced in the code can be detected by formal verification.
Bitcoin is getting a lot of press recently, but let's be honest, that's mostly because a single bitcoin worth 800 USD in January 2017 was worth almost 20,000 USD in December 2017. However, bitcoin and its underlying blockchain are beautiful technologies that are worth a closer look. Let’s take that look with our Ada hat on!
This blog post is part one of a tutorial based on the OpenGLAda project and will cover some the background of the OpenGL API and the basic steps involved in importing platform-dependent C functions.
Fuzzing is a very popular bug finding method. The concept, very simple, is to continuously inject random (garbage) data as input of a software component, and wait for it to crash. If, like me, you find writing robustness test tedious and not very efficient in finding bugs, you might want to try fuzzing your Ada code.Here's a recipe to fuzz-test your Ada code, using American Fuzzy Lop and all the runtime checks your favorite Ada compiler can provide.Let's see (quickly) how AFL works, then jump right into fuzzing 3 open-source Ada libraries: ZipAda, AdaYaml, and GNATCOLL.JSON.
Libadalang has come a long way since the last time we blogged about it. In the past 6 months, we have been working tirelessly on name resolution, a pretty complicated topic in Ada, and it is finally ready enough that we feel ready to blog about it, and encourage people to try it out.
SummaryThe Hexiwear is an IoT wearable development board that has two NXP Kinetis microcontrollers. One is a K64F (Cortex-M4 core) for running the main embedded application software. The other one is a KW40 (Cortex M0+ core) for running a wireless connectivity stack (e.g., Bluetooth BLE or Thread). The Hexiwear board also has a rich set of peripherals, including OLED display, accelerometer, magnetometer, gryroscope, pressure sensor, temperature sensor and heart-rate sensor. This blog article describes the development of a "Swiss Army Knife" watch on the Hexiwear platform. It is a bare-metal embedded application developed 100% in Ada 2012, from the lowest level device drivers all the way up to the application-specific code, for the Hexiwear's K64F microcontroller. I developed Ada drivers for Hexiwear-specific peripherals from scratch, as they were not supported by AdaCore's Ada drivers library. Also, since I wanted to use the GNAT GPL 2017 Ada compiler but the GNAT GPL distribution did not include a port of the Ada Runtime for the Hexiwear board, I also had to port the GNAT GPL 2017 Ada runtime to the Hexiwear. All this application-independent code can be leveraged by anyone interested in developing Ada applications for the Hexiwear wearable device.
This project involves the design of a software platform that provides a good basis when developing motor controllers for brushless DC motors (BLDC/PMSM). It consist of a basic but clean and readable implementation of a sensored field oriented control algorithm. Included is a logging feature that will simplify development and allows users to visualize what is happening. The project shows that Ada successfully can be used for a bare-metal project that requires fast execution.
We have put together a byte (8 bits) of examples of SPARK code on a server in the cloud. The benefit with this webpage is that anyone can now experiment live with SPARK without installing first the toolset. Something particularly interesting for academics is that all the code for this widget is open source. So you can setup your own proof server for hands-on sessions, with your own exercises, in a matter of minutes.
While we are working very hard on semantic analysis in Libadalang, it is already possible to leverage its lexical and syntactic analyzers. A useful example for this is a syntax highlighter.
When things don’t work as expected, developers usually do one of two things: either add debug prints to their programs, or run their programs under a debugger. Today we’ll focus on the latter activity.
A friend pointed me to recent posts by Tommy M. McGuire, in which he describes how Frama-C can be used to functionally prove a brute force version of string search, and to find a previously unknown bug in a faster version of string search called quick search. Frama-C and SPARK share similar history, techniques and goals. So it was tempting to redo the same proofs on equivalent code in SPARK, and completing them with a functional proof of the fixed version of quick search. This is what I'll present in this post.
The Adaroombot project consists of an iRobot CreateⓇ 2 and Ada running on a Raspberry Pi with a Linux OS. This is a great Intro-to-Ada project as it focuses on a control algorithm and a simple serial communications protocol. The iRobot CreateⓇ 2 platform was originally design for STEM education and has great documentation and support - making it very easy to create a control application using Ada. This blog looks at the creation of the project and some cool features of Ada that were learned along the way.
Updated July 2018
Two years ago, we redeveloped the code of a small quadcopter called Crazyflie in SPARK, as a proof-of-concept to show it was possible to prove absence of run-time errors (no buffer overflows, not division by zero, etc.) on such code. The researchers Martin Becker and Emanuel Regnath have raised the bar by developing the code for the autopilot of a small glider in SPARK in three months only. Their paper and slides are available, and they have released their code as FLOSS for others to use/modify/enhance!
A few weeks ago one of my colleagues shared this kickstarter project : The Barisieur. It’s an alarm clock coffee maker, promising to wake you up with a freshly brewed cup of coffee every morning. I jokingly said “just give me an espresso machine and I can do the same”. Soon after, the coffee machine is in my office. Now it is time to deliver :)
After we created lightweight checkers based on the recent Libadalang technology developed at AdaCore, a colleague gave us the challenge of creating a copy-paste detector based on Libadalang. It turned out to be both easier than anticipated, and much more efficient and effective than we could have hoped for. In the end, we hope to use this new detector to refactor the codebase of some of our tools, and we expect to integrate it in our IDEs.
This year again, the VerifyThis competition took place as part of ETAPS conferences. This is the occasion for builders and users of formal program verification platforms to use their favorite tools on common challenges. The first challenge this year was a good fit for SPARK, as it revolves around proving properties of an imperative sorting procedure. In this post, I am using this challenge to show how one can reach different levels of software assurance with SPARK.
In my previous blog article, I exposed some techniques that helped me rewrite the Crazyflie’s firmware from C into Ada and SPARK 2014, in order to improve its safety.
Euclid's algorithm for computing the greatest common divisor of two numbers is one of the first ones we learn in school, and also one of the first algorithms that humans devised. So it's quite appealing to try to prove it with an automatic proving toolset like SPARK. It turns out that proving it automatically is not so easy, just like understanding why it works is not so easy. In this post, I am using ghost code to prove correct implementations of the GCD, starting from a naive linear search algorithm and ending with Euclid's algorithm.
Following the current trend, the GNATcoverage project moves to GitHub! Our new address is: https://github.com/AdaCore/gnatcoverage
GNATprove performs auto-active verification, that is, verification is done automatically, but usually requires annotations by the user to succeed. In SPARK, annotations are most often given in the form of contracts (pre and postconditions). But some language features, in particular ghost code, allow proof guidance to be much more involved. In a paper we are presenting at NASA Formal Methods symposium 2017, we describe how an imperative red black tree implementation in SPARK was verified using intensive auto-active verification.
The Ada Drivers Library (ADL) is a collection of Ada device drivers and examples for ARM-based embedded targets. The library is maintained by AdaCore, with development originally (and predominantly) by AdaCore personnel but also by the Ada community at large. It is available on GitHub and is licensed for both proprietary and non-proprietary use.
At AdaCore, we have a strong expertise in deep static analysis tools (CodePeer and SPARK), and we have been relying on the compiler GNAT and our coding standard checker GNATcheck to deal with more syntactic or weakly-semantic checks. The recent Libadalang technology, developed at AdaCore, provided us with an ideal basis to develop specialized light-weight static analyzers. As an experiment, we implemented two simple checkers using the Python binding of Libadalang. The results on our own codebase were eye-opening: we found a dozen bugs in the codebases of the tools we develop at AdaCore (including the compiler and static analyzers).
AdaCore is working on a host of tools that works on Ada code. The compiler, GNAT, is the most famous and prominent one, but it is far from being the only one. At AdaCore, we already have several other tools to process Ada code: the ASIS library, GNAT2XML, the GPS IDE. A realization of the past years, however, has been that we were lacking a unified solution to process code that is potentially evolving, potentially incorrect Ada code. Hence Libadalang.
There are moments in life where you find yourself with an AdaFruit thermal printer in one hand, and an OpenMV camera in the other.
Judging for the first annual Make with Ada competition has come to an end and we can now reveal the results.
Using Ada technologies to develop video games doesn’t sound like an an obvious choice - although it seems like there could be an argument to be made. The reverse, however, opens some more straightforward perspectives.
The GPS source repository has been published on GitHub. This post briefly describes how you can access it, and hopefully contribute.
If you’ve been looking for a way to start your next embedded project in Ada or SPARK. Then, look no further than the Make with Ada competition!
I started this project more than a year ago. It was supposed to be the first Make with Ada project but it became the most challenging from both, the hardware and software side.
A few months ago, my colleague Rebecca installed a candy dispenser in our kitchen here at AdaCore. I don’t remember how exactly, but I was challenged to make it more… fun.
A step by step tutorial to adapt the ARM runtime to new MCUs/boards.
When the Pebble Time kickstarter went through the roof, I looked at the specification and noticed the watch was running on an STM32F4, an ARM cortex-M4 CPU which is supported by GNAT. So I backed the campaign, first to be part of the cool kids and also to try some Ada hacking on the device.
Through the adoption of GitHub we have taken our first step on the way to having a more collaborative and dynamic interaction with, both our users and open source technologies.
I am very pleased to announce that a book is now available for those who want to learn formal verification with SPARK 2014. This book was written by Prof. John McCormick from University of Northern Iowa and Prof. Peter Chapin from Vermont Technical College. We've been interacting a lot with them since they started in 2013, and the result of these interactions is quite satisfying!
I started out as an electronic musician, so one of my original motivations when I learnt programming was so that I could eventually *program* the sounds I wanted rather than just use already existing software to do it.
July 20, 1969, 8:18 p.m. UTC, while a bunch of guys were about to turn blue on Earth, commander Neil A. Armstrong confirms the landing of his Lunar Module (LM), code name Eagle, on the moon. Will you be able to manually land Eagle on the Sea of Tranquillity?
A few weeks ago I discovered the wonderful world of solenoid engines. The idea is simple: take a piston engine and replace explosion with electromagnetic field. In this article I will experiment a solenoid engine using a hacked hard drive and a software controller on a STM32F4 .
The Crazyflie is a very small quadcopter sold as an open source development platform: both electronic schematics and source code are directly available on their GitHub and its architecture is very flexible. Even if the Crazyflie flies out of the box, it has not been developed with safety in mind: in case of crash, its size, its weight and its plastic propellers won’t hurt anyone! But what if the propellers were made of carbon fiber, and shaped like razor blades to increase the drone’s performance? In theses circumstances, a bug in the flight control system could lead to dramatic events. In this post, I present the work I did to rewrite the stabilization system of the Crazyflie in SPARK 2014, and to prove that it is free of runtime errors. SPARK also helped me to discover little bugs in the original firmware, one of which directly related with overflows. Besides the Crazyflie, this work could be an inspiration for others to do the same work on larger and more safety-critical drones.
Correctness of robot software is a challenge. Just proving the absence of run-time errors (AoRTE) in robot software is a challenge big enough that even NASA has not solved it. Researchers have used SPARK to do precisely that for 3 well-known robot navigation algorithms. Their results will be presented at the major robotics conference IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS 2014) this coming September.