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Technology Decisions, LLC

Technology Decisions, LLCTechnology Decisions, LLCTechnology Decisions, LLC

(608) 556 4230

  • Home
  • More fun...
  • Even more fun!
  • Even More Fun!!
  • More & more fun
  • NASA Mistakes

Software

Operating Systems

 

Operating Systems.  The logic required to do operating systems/coding in general is exquisite, far beyond "an apple is an apple".  That's trivial.  A modern operating system is 10 million lines of code.  Inherently, when something is fixed, something else is broken, keeping all that logic together.
 

Some other examples:

https://en.wikipedia.org/wiki/Therac-25


NASA:

The first space shuttle flight was cancelled 20 minutes before its initial launch.  This was done through the on-board computers.  There were four on-board computers in redundancy which used an operating system called PASS.  As a safety check, there was a fifth, completely independent and designed by an entirely different team.  It used an operating system called BFS.  On the first launch all four PASS computers voted go.  The vote needed to be unanimous for launch.  The BFS computer voted no.  There was nothing wrong with the shuttle and the flight would have been a success.  Upon investigation, engineers discovered a unique example of a classic OS design flaw in the logic of what OS engineers call "synchronization".  How do I get the simplest of systems with two users to operate using shared memory space, which is often necessary, and sometimes useful, to cooperate and function properly to get the result I truly want and NOT the result I THINK the code is going to give me.  Obviously, a computer, being truly, truly, truly, deeply stupid, will only do what you tell it to do.  If it doesn't, it's your fault, and not the computer, always.  NO matter how hard you try to convince yourself it's the computer's.  The issue with BFS was indeterministic, which means it doesn't happen every time, which are the MOST FUN ones!!!!  Some of these logic problems are impossible to diagnose without being used in production.  Impossible.  Such was the case of BFS.  It happened only 1/67 times.

https://spaceflight.nasa.gov/shuttle/reference/shutref/orbiter/avionics/dps/bfs.html

https://www5.in.tum.de/~huckle/space_.pdf


The Mars Rover experienced a "priority inversion issue", which caused it to reboot with frequency:

https://www.rapitasystems.com/blog/what-really-happened-to-the-software-on-the-mars-pathfinder-spacecraft


Mars Climate Orbiter, programming Imperial vs Metric units

https://www.simscale.com/blog/2017/12/nasa-mars-climate-orbiter-metric/ 

https://qz.com/726338/the-code-that-took-america-to-the-moon-was-just-published-to-github-and-its-like-a-1960s-time-capsule/

https://electrek.co/2019/08/01/tesla-faces-wrongful-death-lawsuit-fatal-crash-autopilot-semi-truck/

https://www.theverge.com/2019/5/17/18629214/tesla-autopilot-crash-death-josh-brown-jeremy-banner

https://www.psychologytoday.com/us/blog/getting-proactive/202007/the-1986-challenger-disaster-informs-the-covid-19-pandemic

Liabilities of AI are increasing

Liabilities of AI (pdf)

Download

Cybersecurity & Leadership

Credentials matter

Cybersecurity breaches:


Colonial Pipeline

CIO, Marie Mouchet

Bachelor of Arts and Master of Education degrees in Mathematics from Georgia State University.


Target

CIO, Beth Jacob

BS, Retail Management, University of Minnesota

MBA, Organizational Leadership, University of Minnesota


Equifax

CISO, Susan Mauldin

BA/MA Music Composition, University of Georgia


Home Depot

CIO, Matt Carey

Associate’s degree in information systems from Oklahoma State University – Okmulgee. 


Marriott International

CIO, Bruce Hoffmeister

AS, Computer Science, BS, Mathematics/Biology, Thomas More University

MBA, Finance, Vanderbilt University 

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