AdaCore Blog

44 entries tagged with #Space

by Fabien Chouteau , Emma Adby

AdaCore Code of Conduct

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.

by Pat Rogers

From Ada to Platinum SPARK: A Case Study for Reusable Bounded Stacks

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.

#SPARK    #Ada    #Transitioning to SPARK   

by Quentin Ochem

Witnessing the Emergence of a New Ada Era

For nearly four decades the Ada language (in all versions of the standard) has been helping developers meet the most stringent reliability, safety and security requirements in the embedded market. As such, Ada has become an entrenched player in its historic A&D niche, where its technical advantages are recognized and well understood. Ada has also seen usage in other domains (such as medical and transportation) but its penetration has progressed at a somewhat slower pace. In these other markets Ada stands in particular contrast with the C language, which, although suffering from extremely well known and documented flaws, remains a strong and seldom questioned default choice. Or at least, when it’s not the choice, C is still the starting point (a gateway drug?) for alternatives such as C++ or Java, which in the end still lack the software engineering benefits that Ada embodies..

by Joffrey Huguet

Using SPARK to prove 255-bit Integer Arithmetic from Curve25519

In 2014, Adam Langley, a well-known cryptographer from Google, wrote a post on his personal blog, in which he tried to prove functions from curve25519-donna, one of his projects, using various verification tools: SPARK, Frama-C, Isabelle... He describes this attempt as "disappointing", because he could not manage to prove "simple" things, like absence of runtime errors. I will show in this blogpost that today, it is possible to prove what he wanted to prove, and even more.

#SPARK    #Formal Verification    #Cryptography   

by Peter Chapin

Ten Years of Using SPARK to Build CubeSat Nano Satellites With Students

My colleague, Carl Brandon, and I have been running the CubeSat Laboratory at Vermont Technical College (VTC) for over ten years. During that time we have worked with nearly two dozen students on building and programming CubeSat nano satellites. Because of their general inexperience, and because of the high student turnover rate that is natural in an educational setting, our development process is often far from ideal. Here SPARK has been extremely valuable to us. What we lack in rigor of the development process we make up for in the rigor of the SPARK language and tools. In November 2013 we launched a low Earth orbiting CubeSat. The launch vehicle contained 13 other university built CubeSats. Most were never heard from. One worked for a few months. Ours worked for two years until it reentered Earth's atmosphere as planned in November 2015.

#SPARK    #Space    #Education    #Safety   

by Quentin Ochem

Proving Memory Operations - A SPARK Journey

The promise behind the SPARK language is the ability to formally demonstrate properties in your code regardless of the input values that are supplied - as long as those values satisfy specified constraints. As such, this is quite different from static analysis tools such as our CodePeer or the typical offering available for e.g. the C language, which trade completeness for efficiency in the name of pragmatism. Indeed, the problem they’re trying to solve - finding bugs in existing applications - makes it impossible to be complete. Or, if completeness is achieved, then it is at the cost of massive amount of uncertainties (“false alarms”). SPARK takes a different approach. It requires the programmer to stay within the boundaries of a (relatively large) Ada language subset and to annotate the source code with additional information - at the benefit of being able to be complete (or sound) in the verification of certain properties, and without inundating the programmer with false alarms.

by Rob Tice

The Adaroombot Project

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.

#Raspberry Pi    #ARM    #Linux    #Ada    #Roomba   

by Jorge Real

Writing on Air

While searching for motivating projects for students of the Real-Time Systems course here at Universitat Politècnica de València, we found a curious device that produces a fascinating effect. It holds a 12 cm bar from its bottom and makes it swing, like an upside-down pendulum, at a frequency of nearly 9 Hz. The free end of the bar holds a row of eight LEDs. With careful and timely switching of those LEDs, and due to visual persistence, it creates the illusion of text... floating in the air!

#STM32    #Ravenscar    #Ada    #Makers    #Embedded Development   

by Fabien Chouteau , Arnaud Charlet , Yannick Moy

SPARK Tetris on the Arduboy

One of us got hooked on the promise of a credit-card-size programmable pocket game under the name of Arduboy and participated in its kickstarter in 2015. The kickstarter was successful (but late) and delivered  the expected working board in mid 2016. Of course, the idea from the start was to program it in Ada , but this is an 8-bits AVR microcontroller (the ATmega32u4 by Atmel) not supported anymore by GNAT Pro. One solution would have been to rebuild our own GNAT compiler for 8-bit AVR from the GNAT FSF repository and use the AVR-Ada project. Another solution, which we explore in this blog post, is to use the SPARK-to-C compiler that we developed at AdaCore to turn our Ada code into C and then use the Arduino toolchain to compile for the Arduboy board.

by Pat Rogers

Driving a 3D Lunar Lander Model with ARM and Ada

One of the interesting aspects of developing software for a bare-board target is that displaying complex application-created information typically requires more than the target board can handle. Although some boards do have amazing graphics capabilities, in some cases you need to have the application on the target interact with applications on the host. This can be due to the existence of special applications that run only (or already) on the host, in particular.

#Bareboard    #Embedded Development    #STM32    #Ada   

by Florian Schanda

SPARKSMT - An SMTLIB Processing Tool Written in SPARK - Part I

Today I will write the first article in a short series about the development of an SMTLIB processing tool in SPARK. Instead of focusing on features, I intend to focus on the how I have proved absence of run-time errors in the name table and lexer. I had two objectives: show absence of run-time errors, and do not write useless defensive code. Today's blog will be about the name table, a data structure found in many compilers that can map strings to a unique integer and back. The next blog post will talk about the lexical analyzer.

#Dev Projects    #Formal Verification    #SPARK   

by Karen Mason

What's in the Box?

Forget about the black box - we want you to see what's in the AdaCore box! Our machine room, the life blood of the company, is centered in the office space in a glass box and is pure eye candy for geeks and cable aficionados. The machine room is 204 sq ft (19 sq meters), contains 73 machines (running the gamut from VxWorks, Linux, Windows, Android and more) 1.5 miles of cables and a state of the art fire suppression mechanism! Oh and the modern air intake system gives it a green energy seal of approval. In the unlikely event of a fire; the smoke detectors allow 30 seconds before dispersing an agent called FM200 which will suppress the fire but not damage the equipment. The economizer takes advantage of winters' freeze and draws cool air from the outside to cool the machine room and the heated air is then spilled to common office areas thus reducing heating costs. We're proud to show-off the hardware side of our software!

#cable porn   

by Romain Berrendonner

French Intelligence Bill: A Minority Report

Following the terrorist attacks that occurred in Paris earlier this year, the French government is proposing a bill that will, supposedly, improve the control over intelligence services and give legal ground to some of the intelligence-gathering methods these services are already known to use, ie. render legal, the previously illegal, Internet wiretapping. Interestingly, opponents of the this time bill include not only the usual civil liberty activists such as La Quadrature du Net, Amnesty International or La ligue des droits de l’Homme. Professional trade unions, such as Syntec, companies, such as OVH and even official bodies, such as the CNIL and the Défenseur des droits also expressed an unusually vocal opposition to the proposed bill.

#PJLRenseignement    #Wiretapping    #Freedom of Speech    #Privacy    #Snowden   

by Yannick Moy

SPARK 2014 Rationale: Object Oriented Programming

Object Oriented Programming is known for making it particularly difficult to analyze programs, because the subprograms called are not always known statically. The standard for civil avionics certification has recognized this specific problem, and defines a specific verification objective called Local Type Consistency that should be met with one of three strategies. SPARK allows using one of these strategies, by defining the behavior of an overridden subprogram using a special class-wide contract and checking that the behavior of the overriding subprogram is a suitable substitution, following the Liskov Substitution Principle.

#Language    #Formal Verification    #SPARK