Top all-time · #9680
Rapita Systems
Company blog · rapitasystems.com/blogsystemsprogramming
Rapita Systems is the company blog at rapitasystems.com, writing about systems and programming. Since 2013, 8 different Hacker News readers have linked it 8 times, most often “What really happened to the software on the Mars Pathfinder spacecraft?”. It is still writing: the last post was on 2026-05-20, and you can follow it by feed.
Too few sampled comments (4) to say how often HN recommends it.?
Why HN links it
HN commenters link Rapita's posts on embedded real-time and safety topics, including RTOS priority inversion and the Mars Pathfinder incident, as background for their own points.
Summarised by Claude from a sample of 4 HN comments that link here. Each comment is marked recommending, critical or neutral (citing without judging); how this works.
Most-linked posts?
- What really happened to the software on the Mars Pathfinder spacecraft?2 people · 2 mentions · first linked 2018-08-24
What Hacker News says?
Also, an RTOS is susceptible to priority inversion[0] so it’s not necessarily a panacea. 0. which infamously occurred on the Mars Pathfinder. https://www.rapitasystems.com/blog/what-really-happened-to-t...
Comment linking /blog/what-really-happened-to-the-software-on-the-mars-pathfinder-spacecraft
on “Former Tesla Firmware Engineer Discusses the System”Submitted What really happened to the software on the Mars Pathfinder spacecraft? as a story · 84 points
HN discussionI don't know Python, Go, or nodejs, but with regard to general purpose programming, you can look at some of the free tools and libraries on AdaIC ( https://www.adaic.org/ada-resources/tools-libraries/ ). There is a man named Gautier, who actively develops a variety of tools (e.g. 3D gfx, Excel file producer, games, code editors, etc). Check out his blog page: https://gautiersblog.blogspot.com/search/label/Ada In add…
Comment linking /
on “Airbus Chooses GNAT Pro Ada for Development of Unmanned Aerial System”Submitted What really happened to the software on the Mars Pathfinder spacecraft? as a story · 7 points
HN discussionFriendly neighbourhood aerospace systems engineer here. Yes, the certifications on the aviation side are DO-178C for Software and DO-254 for Airborne Electronic Hardware. Rather than SIL or ASIL (Automotive Safety Integrity Level), the aviation equivalent is DAL (Development Assurance Level). Of course, while they each use letters for levels of Integrity / Assurance, in aviation DAL A is the most stringent and in au…
Comment linking /blog/what%E2%80%99s-difference-between-sil-and-dal-how-does-it-affect-my-code-coverage
on “Released and Certified: Qt Safe Renderer”Submitted What really happened to the software on the Mars Pathfinder spacecraft? as a story · 4 points
HN discussionOK, I get it now. Quite surprising that serialisation is a key performance issue. But then again, pushing signals in and out of CAN frames is also a key performance feature in regular ECUs so I guess that's a universal issue with all sensor/control/actuator systems. Finding the WCET used to be about cycle accurate models but that's long been blown away by the complexity of real hardware. But there's quite a good bit…
Comment linking /products/rapitime
on “Safety Implications of Serialization Timing in Autonomous Vehicles [pdf]”Submitted Breaking the switch statement as a story · 2 points
HN discussion
