Tuesday, October 2, 2018

Cost of highly safety critical software

It's always interesting to see data on industry software costs. I recently came across a report on software costs for the aviation industry. The context was flight-critical radio communications, but the safety standards discussed were DO-178B and DO-254, which apply to flight controls as well.

Here's the most interesting picture from the report for my purposes:


(Source: Page 28 https://www.eurocontrol.int/sites/default/files/content/documents/communications/29012009-certification-cost-estimation-for-fci-platform.pdf.pdf )

Translating from DO-178B terminology, this means:

  • DAL A  (failure would be "catastrophic"):  3 - 12 SLOC/day
  • DAL B  (failure would be "hazardous"): 8 - 20 SLOC/day
  • DAL C (failure would be "major"): 15 - 40 SLOC/day
  • DAL D (failure would be "minor"): 25 - 64 SLOC/day
Worth noting is that, in my experience, really solid mission critical but NOT life-critical embedded software can be done at up to 16 SLOC per day for well-run experienced teams, so it tends to line up with DAL B costs.


For interpretation, "DAL" expresses a criticality level (a "Development Assurance Level"), with more critical software requiring more rigorous processes.  The document has quite a lot to say about how the engineering process works, and is worth a read if you want to see how the aviation folks do business.  (I'm aware that DO-178C is out, but this paper talks about the older "B" version.)    Note that there are other cost models in the paper that are less pessimistic in that report, but this is the one that says "industry experience."

Have you found other cost of software data for embedded or mission critical systems?

Monday, October 1, 2018

A Million Page Views


Blogger analytics say that I just hit 1 million page views.

For fun, the top 10 countries reading this blog in rank order are:
  • USA (about half the total views)
  • Germany (almost tied with India at more than 10%)
  • India (almost tied with Germany at more than 10%)
  • Russia
  • United Kingdom
  • Canada
  • France
  • Ukraine
  • Poland
  • Brazil
I look forward to continuing to post articles about embedded system software, as well as on my Safe Autonomy Blog

Thanks to all the readers who made this happen!