473: Math Is Not the Answer

Philip Koopman joined us to talk about how modulo 255 vs 256 makes a huge difference in checksum error detection, how to get the most out of your checksum or CRC, and why understanding how they work is worth the effort.

Philip has recently published Understanding Checksums and Cyclic Redundancy Checks. He’s better known for Better Embedded System Software as well as his two books about safety and autonomous vehicles:

Phil has many free video lectures with great visuals to go along with his books. He also has three(!) blogs:

Currently, Phil is a professor at Carnegie Mellon University (his page there). You can follow him on LinkedIn. 

Elecia read (and give 2.5 stars to) Symmetry: A Journey into the Patterns of Nature by Marcus du Sautoy: “Interesting but uneven, I kept reading to find out what horrible things math profs do to their children in the name of fun. Worth it when I finally got to a small section with Claude Shannon (and Richard Hamming). It didn’t help with this podcast but it was neat.”

Transcript

Nordic Semiconductor empowers wireless innovation, by providing hardware, software, tools and services that allow developers to create the IoT products of tomorrow. Learn more about Nordic Semiconductor at nordicsemi.com, check out the DevAcademy at academy.nordicsemi.com and interact with the Nordic Devzone community at devzone.nordicsemi.com.

421: Paint the Iceberg Yellow

Chris Hobbs talks with Elecia about safety critical systems. Safety-critical systems keep humans alive. Writing software for these embedded systems carries a heavy responsibility. Engineers need to understand how to make code fail safely and how to reduce risks through good design and careful development. 

The book discussed was Embedded Software Development for Safety-Critical Systems by Chris Hobbs.

This discussion was originally for Classpert (where Elecia is teaching her Making Embedded Systems course) and the video is on Classpert’s YouTube if you want to see faces.

There were many terms with letters and numbers, here is a guide:

  • IEC 61508: Functional Safety of Electrical/Electronic/Programmable Electronic Safety-related Systems; relates to industrial systems and forms the foundation for many other standards 

  • ISO 26262: Road vehicles - Functional Safety; extends and specializes IEC 61508 for systems within cards

  • IEC 62304 specifies life cycle requirements for the development of medical software and software within medical devices. It has been adopted as national standards and therefore can be used as a benchmark to comply with regulatory requirements.

  • MISRA C: a set of software development guidelines for the C programming language 

  • DO178-C and DO178-B: Software Considerations in Airborne Systems and Equipment Certification are the primary documents by which the certification authorities such as FAA, EASA and Transport Canada approve all commercial software-based aerospace systems

  • ISO/IEC 29119: Software and systems engineering -- Software testing

  • ISO 14971:2019 Medical devices — Application of risk management to medical devices (this is the on that was mentioned as a set of useful guidelines for identifying and mitigating hazards during brainstorming)

  • IEC 62304:2006 Medical device software — Software life cycle processes

Transcript

166: Sardine Tornado

Bob Apthorpe (@arclight) spoke with us about software, nuclear engineering, and improv.

Bob is giving away three books! Send in your guess by October 1, 2016. One entry per person. (More info below.)

Hackaday SuperCon is Nov 5-6, in Pasadena, CA.

Bob's long languishing blog is overscope.cynistar.net.

Peep (The Network Aualizer): Monitoring Your Network with Sound

Safety-I and Safety-II: The Past and Future of Safety Management

Now! The books you may win!

Atomic Accidents by James Mahaffrey, someone who knows the technology and history and does a fantastic job explaining complex failures in an engaging way without resorting to fear-mongering and hyperbole. (Guess Elecia's number for this one.)

Safeware by Nancy Leveson, may be 20 years old, it's still full of amazing insights for delivering safe, reliable systems and ways of looking at the organizational contexts in which these systems are built and used. Even if you aren't developing safety-critical systems, it's a fantastic resource and really thought-provoking. (Guess Christopher's number for this one.)

Every Anxious Wave by Mo Daviau is a novel about rock & roll, time travel, love, loss, and finding things you didn't know you were looking for. Full disclosure: The author is Bob's ex-wife. (Guess Bob's number for this one.)