The mystery of IP 217 revealed

Several of you have asked what IP 217 refers to. Below is a description of the Issue Paper supplied by Dewi Daniels from Silver Atena and DO-178C committee participant:

A number of presentations on Open-DO, including “Open-DO: a call to action” posted to the Open-DO web site, have mentioned something called IP 217 and several people have asked, “What is IP 217?”. Well, IP 217 was an (infamous) Issue Paper produced as part of the DO-178C/ED-12C standardisation effort.

As you know, DO-178B/ED-12B describes two levels of software requirements, which it calls high-level requirements and low-level requirements. It’s not very clear in DO-178B/ED-12B how high-level requirements are related to low-level requirements, or how the low-level requirements are related to the software architecture. DO-178B/ED-12B also requires that derived requirements be provided to the system safety assessment process, but the definition of derived requirements in DO-178B/ED-12B is ambiguous, while the term has a different meaning in the wider software engineering community.

IP 217 tried to develop a more formal model of requirements and design that could be incorporated in DO-178C/ED-12C. It proposed a tiered model of requirements and design that could be applied to systems engineering as well as to software engineering. The concepts in IP 217 were eventually rejected for incorporation in DO-178C/ED-12C because they would have resulted in too big a change to implement in the time available. We’ve had a lot of encouragement from a number of people to continue to develop the concepts in IP 217.

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One Comment

  1. Robert Busser
    Posted November 21, 2016 at 22:08 | Permalink

    A better and more quantitative explanation as to why we were unable to get the concepts presented in IP 217 is that the TOR (basically the overall rules for producing DO- 178C) was a requirement that fundamental core document changes be approved by about 95% of the plenary group and IP-217 only achieved about 70% approval.

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